<PAGE>

                                                                    EXHIBIT 4.23

               Master Development and Purchase Agreement Between
        Harrah's Operating Company, Inc. and Mikohn Gaming Corporation

     This Master Development and Purchase Agreement (the "Master Agreement")
between Harrah's Operating Company, Inc., a Delaware corporation ("HOC") and
Mikohn Gaming Corporation, a Nevada corporation ("MIKN"), is entered into as of
April 27, 1998 (the "Effective Date").

                                   Recitals

     A. HOC is owner of all rights, title and interest in and to certain
intellectual property rights related to a patented system for the tracking of
players and management of information in connection with live table gaming,
known as "Total Track", bearing U.S. patent number 5,613,912, and a related
patent application, software, documentation and specifications.

     B. HOC and MIKN desire that MIKN assist HOC in the completion of the
development of certain hardware and software for Total Track and that MIKN
develop related computer and network systems for the tracking of players and
management of information in connection with live table gaming, which integrate
Total Track with MIKN's proprietary "SafeTrack" system and integrate Total Track
with MIKN's proprietary "SafeJack" system.

     C. Upon completion of MIKN's development efforts, MIKN desires to sell and
HOC desires to purchase from MIKN Total Track, the integrated Total
Track/SafeTrack system, the integrated Total Track/SafeJack System, and various
maintenance and other related services accompanying such products.

     D. Contemporaneously with this Master Agreement, the parties are entering
into (i) an Intellectual Property License Agreement which is attached hereto in
Exhibit A and which grants MIKN, among other things, a license to use certain
intellectual property rights owned by HOC relating to Total Track , and (ii) a
Registration Rights Agreement which is attached hereto in Exhibit C and which
governs certain obligations of MIKN and rights of HOC with respect to
registration of MIKN common shares with the Securities Exchange Commission.

     NOW, THEREFORE, in consideration of the mutual promises and of the
performance of the mutual covenants contained herein, the parties agree as
follows:

1.   DEFINITIONS

     1.1 "Additional License Fee" shall have the definition provided in Section
          ----------------------
8.1.2.

     1.2 "Additional Components" means the additions to the Base TT System
          ---------------------
described in Section 2.3.

     1.3 "Affiliate" means any person or entity Controlling, Controlled by or
          ---------
under common Control with, directly or indirectly, another person or entity. For
purposes of this


<PAGE>

definition, "Control" means the power to direct the management or affairs of a
person or entity by voting securities, membership interests or similar
interests, by contract or otherwise.

     1.4  "Arbitrable Matters" shall have the definition provided in Section 11.
           ------------------

     1.5  "Base TT System" means the system of computer and network software and
           --------------
hardware for the tracking of players and management of information in connection
with live table gaming as known as "Total Track" as delivered by HOC to MIKN on
or about the Closing Date, the components of which are listed on the attached
Exhibit K.

     1.6  "Base TT System Table" means a live gaming table connected to the Base
           --------------------
TT System.

     1.7  "Base TT System Technology" means all designs, algorithms, procedures,
           -------------------------
know how, software, schematics, specifications, prototypes, and other tangible
embodiments of technology relating to the design, development, use, installation
and testing of the Base TT System owned or licensable by HOC as of the Closing
Date.

     1.8  "Bonus License Fee" shall have the definition provided in Section
           -----------------
8.1.3.

     1.9  "Closing Date" means the date upon which this Master Agreement, the
           ------------
License Agreement, and the Registration Rights Agreement have been executed by
both HOC and MIKN.

     1.10 "Common Stock Event" shall have the definition provided in Section
           ------------------
8.1.4.

     1.11 "Confidential Information" means, with respect to either party, this
           ------------------------
Master Agreement, the License Agreement, the Registration Rights Agreement, the
Service and Maintenance Agreements and any confidential business and technical
information, whether or not patentable or copyrightable, that the disclosing
party identifies as confidential or proprietary at the time it is disclosed or
delivered to the receiving party or which the receiving party has reason to know
the disclosing party would like to keep confidential for business reasons, such
as maintenance of a competitive advantage or protection of intellectual property
rights. Confidential Information will not include any information that was
rightfully known to the receiving party before the receiving party's access to
such information hereunder, or that the receiving party rightfully receives from
a third party not under obligation of confidentiality, or that is or becomes
publicly known or available other than as a result of a breach of this Master
Agreement.

     1.12 "Deficiencies" shall have the definition provided in Sections 2.2.1
           ------------
and 2.4.

     1.13 "Event of Default of MIKN" shall have the definition provided in
           ------------------------
Section 10.2.

     1.14 "Event of Default of HOC" shall have the definition provided in
           -----------------------
Section 10.4.

     1.15 "Final TT Specifications" means the functional design specifications
           -----------------------
for the hardware and software components of the TT System, including the
Preliminary TT

                                       2
<PAGE>

Specifications and such changes or additions to these specifications created to
specify the Additional Components and such other changes or additions to which
the parties may agree pursuant to Section 2.1 below.

     1.16 "First AC Deficiency Correction Period" shall have the definition
           -------------------------------------
provided in Section 2.4.

     1.17 "First TT Deficiency Correction Period" shall have the definition
           -------------------------------------
provided in Section 2.2.2.

     1.18 "HOC Properties" refers to casino properties owned, managed or
           --------------
franchised by HOC or its Affiliates.

     1.19 "Initial License Fee" shall have the definition provided in Section
           -------------------
8.1.

     1.20 "Initial Market Price" shall be computed by taking the average of the
           --------------------
high and low price of MIKN Shares on the NASDAQ National Market System on the
last trading day prior to the Closing Date.

     1.21 "Initial Twelve Month Period" shall have the definition provided in
           ---------------------------
Section 7.1.3.

     1.22 "License Agreement" means the license agreement attached hereto in
           -----------------
Exhibit A to be executed by HOC and MIKN contemporaneously with this Agreement.

     1.23 "License Fees" means, collectively, the fees set out in Section 8.
           ------------

     1.24 "Licensed Patents" shall have the definition provided in Section 1.5
           ----------------
of the License Agreement.

     1.25 "Service and Maintenance Agreements" means any agreement between an
           ----------------------------------
HOC Property and MIKN entered into pursuant to Sections 4.3 and 4.4 below with
respect to the service and maintenance of the Base TT System, TT System, TT/ST
System and/or TT/SJ System.

     1.26 "Mikohn Shares" means the common stock of Mikohn Gaming Corporation, a
           -------------
corporation existing under the laws of Nevada, having a par value of $0.10 each,
each of which is, or shall be when transferred to HOC, validly issued, fully
paid and non-assessable and which common stock is listed for open market trading
on the NASDAQ National Market System.

     1.27 "Minimum" shall have the definition provided in Section 6.1.
           -------

     1.28 "Minimum Date" shall have the definition provided in Section 6.1.
           ------------

     1.29 "Preliminary TT Specifications" means the functional design
           -----------------------------
specifications for the hardware and software components of the Base TT System,
which are attached hereto as Exhibit F.

     1.30 "Registration Rights Agreement" means the registration rights
           -----------------------------
agreement attached

                                       3
<PAGE>

hereto in Exhibit C to be executed by HOC and MIKN contemporaneously with this
Agreement.

     1.31 "SafeJack System" means MIKN's hardware and software product known as
           ---------------
"SafeJack".

     1.32 "SafeTrack System" means MIKN's hardware and software product known as
           ----------------
"SafeTrack," which enables the tracking of actual bets of players using chips at
live gaming tables.

     1.33 "Second AC Deficiency Correction Period" shall have the definition
           --------------------------------------
provided in Section 2.4.

     1.34 "Second TT Deficiency Correction Period" shall have the definition
           --------------------------------------
provided in Section 2.2.1.

     1.35 "Service and Maintenance Agreement" means the form of service and
           ---------------------------------
maintenance agreement attached in Exhibit E hereto, pursuant to which MIKN will
render service and maintenance with respect to the Base TT System, the TT
System, the TT/ST System and the TT/SJ System at the various HOC Properties.

     1.36 "Substantially Equivalent" means with respect to persons, the same
           ------------------------
number of persons assigned to a project or task by each party and with respect
to money, to equal contributions of money by each party at on or about the same
time.

     1.37 "TT Acceptance Tests" means the acceptance tests and test protocols
           -------------------
for the Base TT System and the Additional Components to be mutually agreed upon
by HOC and MIKN pursuant to Section 2.1 below.

     1.38 "TT System Development Schedule" means the schedule for development of
           ------------------------------
the TT System set forth in Exhibit B.

     1.39 "TT System" means both the Base TT System in the form as accepted by
           ---------
MIKN pursuant to Section 2.2.1 and such Base TT System with the Additional
Components. The parties shall complete an Exhibit G which shall list the
components of the TT System and the Final TT Specifications.

     1.40 "TT System Table" means a live gaming table connected to the TT
           ---------------
System.

     1.41 "TT/SJ Acceptance Tests" means the acceptance tests and test protocols
           ----------------------
for the TT/SJ System to be mutually agreed upon by HOC and MIKN pursuant to
Section 3.4.

     1.42 "TT/SJ Schedule" means the schedule for development of the TT/SJ
           --------------
System as developed by the parties pursuant to Section 3.4.

     1.43 "TT/SJ Specifications" means the functional design specifications for
           --------------------
the hardware and software components of the TT/SJ System as developed by the
parties pursuant to Section 3.4.

                                       4
<PAGE>

     1.44 "TT/SJ System" means the system of computer and network software and
           ------------
hardware, including a minimum of seven hundred (700) specialized gaming tokens
or chips containing RF transmitters, in denominations as specified by HOC, for
the tracking of players and management of information in connection with live
table gaming resulting from MIKN's obligations hereunder to integrate the TT
System with MIKN's SafeJack System. Following such integration, the parties
shall complete an Exhibit I which shall list the components of the TT/SJ System
and the TT/SJ Specifications.

     1.45 "TT/SJ System Table" means a live gaming table connected to the TT/SJ
           ------------------
System.

     1.46 "TT/ST Acceptance Tests" means the acceptance tests and test protocols
           ----------------------
for the TT/ST System to be mutually agreed upon by HOC and MIKN pursuant to
Section 3.1 below.

     1.47 "TT/ST Schedule" means the schedule for development of the TT/ST
           --------------
System to be agreed to by the parties pursuant to Section 3.1 below.

     1.48 "TT/ST Specifications" means the functional design specifications for
           --------------------
the hardware and software components of the TT/ST System as developed by the
parties pursuant to Section 3.1.

     1.49 "TT/ST System" means the system of computer and network software and
           ------------
hardware, including a minimum of seven hundred (700) specialized gaming tokens
or chips containing RF transmitters, in denominations as specified by HOC, for
the tracking of players and management of information in connection with live
table gaming resulting from MIKN's obligations hereunder to integrate the TT
System with MIKN's SafeTrack System. Following such integration, the parties
shall complete an Exhibit D which shall list the components of the TT/ST System
and the TT/ST Specifications.

     1.50 A "TT/ST System Table" means a live gaming table connected to the
             ------------------
TT/ST System.

     1.51 "TT System Intellectual Property Rights" shall have the definition
           --------------------------------------
provided in Section 1.15 of the License Agreement.

     1.52 "Turnover Date" shall have the definition provided in Section 2.2.
           -------------

2.   TURNOVER AND DEVELOPMENT OF THE BASE TT SYSTEM AND THE TT SYSTEM

     2.1 TT Specifications. Within [] days after the Closing Date, the parties
         -----------------
will agree in writing to the TT Acceptance Tests for the Base TT System. Within
[] days after the Closing Date, the parties will agree in writing to the Final
TT Specifications and the TT Acceptance Tests for the Additional Components.
Once agreed, modifications may not be made to the Final TT Specifications
without both parties' prior written consent. If any subsequent modification to
the Final TT Specifications materially increases the cost to MIKN to develop or
manufacture the TT

                                       5
<PAGE>

System, HOC and MIKN shall enter into good faith negotiations to agree upon
appropriate adjustments to the prices HOC shall pay for the TT System hereunder.

     2.2   Timing of the Turnover of the Base TT System. The parties agree to
           --------------------------------------------
use reasonable commercial efforts and Substantially Equivalent resources to
complete the turnover to MIKN of the installation, maintenance and further
development (as described herein) of the Base TT System software and hardware
within [] days after the Closing Date (the "Turnover Date"). The parties shall
                                            -------------
exert commercially reasonable efforts in good faith to achieve the Turnover
Date. It is understood, however, that HOC's initial installation of the Base TT
System in Atlantic City, NJ is not fully operational as of the Closing Date.
Accordingly, both parties agree that should the time necessary to make it fully
operational materially and adversely impact the parties' achieving the Turnover
Date, HOC and MIKN will mutually agree in writing to a revised Turnover Date.

     2.2.1 Acceptance by MIKN of the Base TT System. On or within [] days
           ----------------------------------------
following the Closing Date, MIKN and HOC will jointly commence the TT Acceptance
Tests on the Base TT System at HOC's Affiliates' casino in Lake Tahoe, Nevada.
As part of the TT Acceptance Tests, MIKN and HOC will test and evaluate the Base
TT System in order to ensure that it conforms to the Preliminary TT
Specifications. Within [] days after commencement of the TT Acceptance Tests,
MIKN shall deliver a written acceptance to HOC or schedule a meeting with HOC to
occur on or before such [] day to discuss non-conformities between the Base TT
System and the Preliminary Specifications or any other deficiency in the Base TT
System that causes it not to pass all of the applicable TT Acceptance Tests
(such non-conformities and deficiencies will be referred to collectively as
"Deficiencies"). At the conclusion of such meeting, MIKN shall approve of the
 ------------
Base TT System or shall specify Deficiencies. Within a mutually agreed time
period after such meeting (the "First TT Deficiency Correction Period"), not to
                                -------------------------------------
exceed [    ] days, HOC will exert best efforts to correct the Deficiencies
so that the Base TT System conforms to the Preliminary TT Specifications and
passes all of the applicable TT Acceptance Tests. If the Deficiencies are not
corrected within such First TT Deficiency Correction Period, HOC and MIKN will
again meet in person to review the Base TT System. At the conclusion of such
meeting, MIKN shall approve the Base TT System or shall specify Deficiencies. If
MIKN specifies Deficiencies, HOC will exert best efforts to correct the
Deficiencies within a mutually agreed time period, not to exceed [] days
("Second TT Deficiency Period"). If the Deficiencies are not corrected within
  ---------------------------
such Second Deficiency Period, HOC and MIKN will meet in person to review the
Base TT System. At the conclusion of such meeting, MIKN shall approve of the
Base TT System or shall specify Deficiencies. If MIKN specifies Deficiencies,
MIKN may, at its sole discretion, (i) extend the TT Deficiency Correction Period
for the Deficiencies by a period determined by MIKN and permit the foregoing
procedure to be repeated until MIKN accepts the Base TT System or finally
rejects the Base TT System, or (ii) terminate this Agreement, the Registration
Rights Agreement and the License Agreement, and, upon such termination(s), HOC
shall return and deliver to MIKN the Initial License Fee, and HOC shall
thereafter have no further liability of any kind to MIKN resulting from or
arising out of such termination, and MIKN shall return to HOC all tangible
embodiments of the Base TT System Technology within MIKN's possession or
control. MIKN shall notify HOC in writing in the event that MIKN accepts the
Base TT System as having passed all of the applicable TT Acceptance Tests.
Following the successful conclusion of the TT Acceptance Tests on the Base TT
System, MIKN will not make any modifications to the Base TT System without HOC's
prior


                                       6
<PAGE>

written consent. If MIKN does not approve or reject the Base TT System or
specify in writing Deficiencies requiring correction within [] after the
commencement of the TT Acceptance Tests or the conclusion of a Deficiency
Correction Period, the Base TT System shall be deemed approved by MIKN.

     2.3 Joint Completion of Additional Components to the TT System. The parties
         ----------------------------------------------------------
shall, within [] days of the Closing Date: (i) agree upon the resources
necessary and schedule for completing development and acceptance testing of; and
(ii) thereafter devote mutually agreed upon Substantially Equivalent resources
to achieve completion of the following components of the TT System (the
"Additional Components"):
 ---------------------

          (a)  Development and testing of software for games other than

          blackjack;

          (b)  Engineering of card reader placements for games other than

          blackjack;

          (c)  "Total View" functionality;

          (d)  Table accounting transaction entry screens and messaging to HOC's

          Casino Management System; and

          (e)  In-rail card readers.

     MIKN shall notify HOC when MIKN has determined that the Additional
Components are ready for administration of the TT Acceptance Tests.

     2.4  Acceptance by HOC of the Additional Components. Upon notification by
          ----------------------------------------------
MIKN pursuant to Section 2.3 above that the Additional Components are ready for
the commencement of the TT Acceptance Tests and consistent with the schedule set
forth on Exhibit B, MIKN and HOC will jointly conduct the TT Acceptance Tests on
the Additional Components. As part of the TT Acceptance Tests, HOC will test and
evaluate the Additional Components in order to ensure that the Additional
Components conform to the applicable part of the Final TT Specifications. Within
[] days after commencement of the TT Acceptance Tests, HOC shall deliver a
written acceptance to MIKN, or schedule a meeting with MIKN to occur on or
before such [] day to discuss non-conformities between the Additional Components
and the Final TT Specifications or any other deficiency in the Additional
Components that causes them not to pass all of the applicable TT Acceptance
Tests (such non-conformities and deficiencies will be referred to collectively
as "Deficiencies"). At the conclusion of such meeting, HOC shall approve of the
    ------------
Additional Components or shall specify Deficiencies. Within a mutually agreed
time period after such meeting (the "First AC Deficiency Correction Period"),
                                     -------------------------------------
not to exceed [    ] days, MIKN will exert best efforts to correct the
Deficiencies so that the Additional Components conform to the Final TT
Specifications and pass all of the applicable TT Acceptance Tests. If the
Deficiencies are not corrected within such First AC Deficiency Correction
Period, HOC and MIKN will meet in person to review the Additional Components. At
the conclusion of such meeting, HOC shall approve the Additional Components or
shall



                                       7

<PAGE>


specify Deficiencies. If HOC specifies Deficiencies, MIKN will exert best
efforts to correct the Deficiencies within a mutually agreed time period, not to
exceed [] days (the "Second AC Deficiency Correction Period"). If the
                     --------------------------------------
Deficiencies are not corrected within such Second AC Deficiency Correction
Period, HOC and MIKN will meet in person to review the Additional Components. At
the conclusion of such meeting, HOC shall approve of the Additional Components
or shall specify Deficiencies. If HOC specifies Deficiencies, HOC may, at its
sole discretion, (i) extend the Second AC Deficiency Correction Period for the
Deficiencies by a period determined by HOC and permit the foregoing procedure to
be repeated until HOC accepts the Additional Components or finally rejects the
Additional Components, or (ii) exercise its rights and remedies under Section
10.3 hereof. HOC shall notify MIKN in writing in the event that HOC accepts the
Additional Components as having passed all of the applicable TT Acceptance
Tests. Following successful completion of the TT Acceptance Tests, MIKN will not
make any modifications to the Additional Components without both parties' prior
written consent. If HOC does not approve or reject the Additional Components or
specify in writing Deficiencies requiring correction within [] days after the
commencement of the TT Acceptance Tests or the conclusion of a Deficiency
Correction Period, the Additional Components shall be deemed approved by HOC.

     2.5 Transition of the Base TT System. As expeditiously as possible after
         --------------------------------
the Closing Date, HOC will transfer to MIKN one (1) copy of the tangible
embodiments of the Base TT System Technology within HOC's possession or control.
Between the Closing Date and the Turnover Date, but as expeditiously as
reasonably possible, the parties will work together to facilitate a smooth and
efficient transfer to MIKN of the know how concerning the Base TT System.
Following the Turnover Date, in order to facilitate the development contemplated
by Section 2.3, HOC agrees to devote a reasonable amount of time of its
personnel who are knowledgeable about the Base TT System to be available to MIKN
to answer questions concerning the Base TT System and the design and use thereof
to personnel of MIKN who will be involved in the further development and service
and maintenance of the Base TT System.

     2.6 Development Resources and Expenses. Except as expressly stated in this
         ----------------------------------
Agreement or otherwise mutually agreed, each party will be responsible for its
own costs incurred in the development of the Base TT System, the TT System, the
TT/ST System and the TT/SJ System and will pay for the costs of the personnel,
materials, facilities and equipment it contributes to the Base TT System, the TT
System, the TT/ST System and the TT/SJ System development effort.

     2.7 Schedule. Exhibit B hereto lists the dates set forth in this Section 2
         --------
and in Section

3.   DEVELOPMENT OF THE TT/ST SYSTEM AND TT/SJ SYSTEM

     3.1 TT/ST Specifications. Within a mutually agreeable time following the
         --------------------
Closing Date, the parties will agree in writing to the TT/ST Specifications, the
TT/ST Schedule and the TT/ST Acceptance Tests for the TT/ST System. Once
developed, no modifications may be made to the TT/ST Specifications without both
parties' prior written consent.

     3.2 Development of the TT/ST System. MIKN shall exert commercially
         -------------------------------
reasonable efforts to develop the TT/ST System in accordance with the TT/ST
Specifications and the TT/ST

                                       8
<PAGE>

Schedule for acceptance testing of the TT/ST System by HOC. Development of the
TT/ST System shall be complete within a mutually agreed upon time after the
Closing Date. MIKN shall notify HOC when MIKN has determined that the TT/ST
System is ready for administration of the TT/ST Acceptance Tests.

     3.3 Acceptance by HOC of the TT/ST System. Upon notification by MIKN
         -------------------------------------
pursuant to Section 3.2 above that the TT/ST System is ready for the
commencement of the TT/ST Acceptance Tests, MIKN and HOC will jointly conduct
the TT/ST Acceptance Tests on the TT/ST System. The TT/ST Acceptance Tests shall
be conducted in accordance with the procedures set forth in Section 2.4 above,
except that references therein to the Additional Components, the Final TT
Specifications and the TT Acceptance Tests shall be deemed to be references,
respectively, to the TT/ST System, the TT/ST Specifications and the TT/ST
Acceptance Tests. HOC shall notify MIKN in writing in the event that HOC accepts
the TT/ST System as having passed all of the TT/ST Acceptance Tests.
Notwithstanding the foregoing, in the event HOC rejects the TT/ST System, its
rights and remedies under Section 10.3(b) hereof shall be limited to terminating
this Agreement only as it pertains to HOC's obligations respecting field testing
the TT/ST System under Section 6.2.

     3.4 TT/SJ Specifications. Within a mutually agreeable time following the
         --------------------
Closing Date, the parties will agree in writing to the TT/SJ Specifications, the
TT/SJ Schedule and the TT/SJ Acceptance Tests for the TT/SJ System. Once
developed, no modifications may be made to the TT/SJ Specifications without both
parties' prior written consent.

     3.5 Development of the TT/SJ System. MIKN shall exert commercially
         -------------------------------
reasonable efforts to develop the TT/SJ System in accordance with the TT/SJ
Specifications and the TT/SJ Schedule for acceptance testing by HOC. Development
of the TT/SJ System shall be complete within a mutually agreed upon time after
the Closing Date. MIKN shall notify HOC when MIKN has determined that the TT/SJ
System is ready for administration of the TT/SJ Acceptance Tests.

     3.6 Acceptance by HOC of the TT/SJ System. Upon notification by MIKN
         -------------------------------------
pursuant to Section 3.5 above that the TT/SJ System is ready for the
commencement of the TT/SJ Acceptance Tests, MIKN and HOC will jointly conduct
the TT/SJ Acceptance Tests on the TT/SJ System. The TT/SJ Acceptance Tests shall
be conducted in accordance with the procedures set forth in Section 2.4 above,
except that references therein to the Additional Components, the Final TT
Specifications and the TT Acceptance Tests shall be deemed to be references,
respectively, to the TT/SJ System, the TT/SJ Specifications and the TT/SJ
Acceptance Tests. HOC shall notify MIKN in writing in the event that HOC accepts
the TT/SJ System as having passed all of the TT/SJ Acceptance Tests.
Notwithstanding the foregoing, in the event HOC rejects the TT/SJ System, its
rights and remedies under Section 10.3(b) hereof shall be limited to terminating
this Agreement only as it pertains to HOC's obligations respecting field testing
the TT/SJ System under Section 6.2.


4.   SERVICE, MAINTENANCE, AND REGULATORY OBLIGATIONS OF MIKN

     4.1 Assumption by MIKN of Obligations for Service and Maintenance. Upon the
         -------------------------------------------------------------



                                       9
<PAGE>

Turnover Date, as defined in Section 2.2 above, MIKN will assume full
responsibility for installing, servicing and maintaining the Base TT System
software and hardware previously installed or thereafter installed in any HOC
Property.

     4.2 Maintenance of a TT System, TT/ST System and TT/SJ System Test Bed. For
         ------------------------------------------------------------------
so long as MIKN is the exclusive provider of service and maintenance for the TT
System, TT/ST System and TT/SJ System for HOC, MIKN shall, on or before
installation of the first of each of a TT System Table, TT/ST System Table or a
TT/SJ System Table at a HOC Property, maintain a software test bed at MIKN's
engineering headquarters in Las Vegas, NV which mirrors the version of the TT
System, TT/ST System and TT/SJ System used by HOC at any given time. MIKN agrees
to maintain such test bed for the purpose of (i) allowing MIKN to duplicate and
correct any problems with the TT System, TT/ST System and TT/SJ System
experienced by HOC in actual operation, and (ii) serving as a resource for
making improvements and enhancements to the TT System, TT/ST System and TT/SJ
System, as HOC may request from time to time. MIKN and HOC shall agree in
advance in writing on any payment obligations for such improvements and
enhancements.

     4.3 Service and Maintenance of the Base TT System, TT System, the TT/ST
         -------------------------------------------------------------------
System and the TT/SJ System. MIKN shall have the obligation to provide service
---------------------------
and maintenance of the Base TT System, TT System, TT/ST System and TT/SJ System
in accordance with the provisions of the Service and Maintenance Agreements
attached as Exhibit E hereto.

     4.4 Service and Maintenance Agreements. HOC and MIKN shall enter into
         ----------------------------------
separate Service and Maintenance Agreements with respect to each of the various
HOC Properties for service and maintenance of the Base TT and/or TT and/or TT/ST
Systems and/or TT/SJ Systems.

     4.5 Regulatory Approval. During the term of this Agreement, MIKN will: (x)
         -------------------
diligently seek, obtain and maintain the approval or license of any regulatory
authority in a jurisdiction which is material to the business of HOC that may be
required to enable the development, testing, implementation, and/or commercial
sale, licensing or distribution and/or use of the: (i) Base TT System; (ii) TT
System; (iii) TT/ST System; and (iv) the TT/SJ System; and (y) shall otherwise
comply with all other relevant gaming or other regulatory requirements. A
jurisdiction is deemed to be "material to the business of HOC if it is: (a) a
jurisdiction in which HOC is doing business at the time such failure to comply
with (x) or (y) occurs; or (b) one in which HOC has publicly announced plans to
do business at the time such failure to comply with (x) or (y) occurs; or (c)
one in which MIKN's failure to comply with (x) or (y) above will adversely
impact HOC in either of (a) or (b).


5.   ENHANCEMENTS TO HOC'S CASINO MANAGEMENT SYSTEM

     HOC shall exert commercially reasonable efforts at its sole expense to
develop and implement any enhancements that need to be made to HOC's Casino
Management System in order to complete development of the TT System, the TT/ST
System and the TT/SJ System or to interface HOC's Casino Management System
thereto in a manner and time frame that does not interfere with MIKN's ability
to meet its obligations under this Agreement.

                                       10
<PAGE>

                                 [BLANK PAGE]

                                       11
<PAGE>

6.   HOC COMMITMENTS TO PURCHASE AND INSTALL SYSTEMS

     6.1 Minimum Installation. On or before the later of: [] ([] the "Minimum
         --------------------                                         -------
Date"), HOC agrees to have installed any combination of [] Base TT System Tables
----
and/or TT System Tables and/or TT/ST System Tables and/or TT/SJ System Tables in
HOC Properties, inclusive of Base TT System Tables and/or TT System Tables
and/or TT/ST System Tables installed prior to the Closing Date or pursuant to
Section 6.2 (the "Minimum"). So long as MIKN maintains exclusivity under the
                  -------
License Agreement, MIKN shall be HOC's exclusive source of supply for all
hardware and software comprising the Base TT System, and the TT, TT/ST and TT/SJ
Systems. So long as MIKN maintains exclusivity under the License Agreement, for
the first [] years after the Turnover Date, MIKN shall be HOC's exclusive source
for servicing and maintaining such hardware and software pursuant to Service and
Maintenance Agreements. In the event HOC fails to install the Minimum on or
before the Minimum Date, MIKN may, at its option, as its sole remedy, either;
(i) declare and deem all License Fees due under Article 8 hereof fully paid up,
in which event MIKN's license rights under the License Agreement shall become
[]; (ii) require HOC to pay MIKN a sum equal to [] ; or (iii) waive HOC's
failure to install the Minimum.

     6.2 Field Trials. Within the [] months following the Turnover Date, at
         ------------
MIKN's request, HOC shall allow MIKN to install for field trial and evaluation
purposes TT/ST System Tables and TT/SJ System Tables comprising at least [].
MIKN shall be HOC's exclusive source of supply for all hardware and software
comprising the TT/ST System Tables and TT/SJ System Tables for such field trial
and shall be HOC's exclusive source for servicing and maintaining such hardware
and software. HOC shall permit the TT/ST System Tables installed in accordance
with this Section 6.2 to remain installed at the foregoing HOC Properties for
such period of time as may be reasonably necessary for MIKN to obtain any
required regulatory approvals in each respective jurisdiction. MIKN shall be
responsible for, shall pay for and shall exert commercially reasonable efforts
to obtain such regulatory approvals as expeditiously as reasonably possible. HOC
shall pay for the TT/ST System Tables and TT/SJ System Tables installed under
this Section 6.2 in accordance with the provisions in Section 7. HOC shall
cooperate with MIKN in operating and presenting the TT/ST System Tables to
regulatory authorities to facilitate prompt approval.

7.   PRICING

     7.1 Price for Systems. During the term of this Master Agreement and subject
         -----------------
to Section 7.5, MIKN agrees to sell Base TT System Tables, TT System Tables,
TT/ST System Tables and TT/SJ System Tables to HOC at the following prices
(subject to Section 7.4):

         7.1.1 Base TT System Table or TT System Table. For a Base TT System
               ---------------------------------------
Table or TT System Table, [] per Base TT System Table or TT System Table,
including training and installation, but excluding wiring (both network and to
the table), duties, shipping and sales tax. HOC shall provide one (1) technician
for every MIKN installer to assist with installation. MIKN shall provide a
software license, service and maintenance, including parts and labor, for a Base
TT System Table or TT System Table for a combined total of [] per month per Base
TT System Table or TT System Table.

                                       12
<PAGE>

         7.1.2 TT/ST System Table. For a TT/ST System Table, [] per system,
               ------------------
including training and installation, but excluding wiring (both network and to
the table), duties, shipping and sales tax. HOC shall provide one (1) technician
for every MIKN installer to assist with installation. MIKN shall provide a
software license, service and maintenance, including parts and labor, for a
TT/ST System Table for a combined total of [] per month per TT/ST System Table.

         7.1.3 TT/SJ System Table. For a TT/SJ System Table, [] per system,
               ------------------
including training and installation, but excluding wiring (both network and to
the table), duties, shipping and sales tax. HOC shall provide one (1) technician
for every MIKN installer to assist with installation. MIKN shall provide a
software license, service and maintenance, including parts and labor, for a
TT/SJ System Table for a combined total of [] per month per TT/SJ System Table
for any TT/SJ System Table ordered within [] months after HOC's acceptance of
the TT/SJ System (the "Initial Twelve Month Period"), and thereafter for a
combined total of [] per month per TT/SJ System Table.

     7.2 Computer Network Equipment. The pricing set forth in Sections 7.1.1,
         --------------------------
7.1.2 and 7.1.3 above does not include computer servers and computer networking
equipment which, at the option of HOC, shall be provided (i) by HOC at no cost
to MIKN or (ii) by MIKN at cost plus a [] handling charge.

     7.3 Spare Parts Inventory. The pricing set forth in Sections 7.1.1, 7.1.2
         ---------------------
and 7.1.3 does not include an inventory of spare and replacement parts. HOC
agrees to create and pay for an initial inventory of spare and replacement parts
at each of the HOC Properties, the size and contents of which shall be specified
in the applicable Service and Maintenance Agreement. For so long as HOC has a
Service and Maintenance Agreement in effect at an HOC Property, HOC shall have
no obligation to restock the inventory of spare and replacement parts at such
HOC Property. Instead MIKN shall replenish such inventory at its sole expense in
accordance with the Service and Maintenance Agreement.

     7.4 Most Favored Nation. During the term of this Agreement, MIKN warrants
         -------------------
and agrees that: (i) all prices to HOC for Base TT System Tables, TT System
Tables, TT/ST System Tables and TT/SJ System Tables will be [].

     7.5 Price Protection.
         ----------------

         7.5.1 Hardware and Installation. MIKN will not increase HOC's prices
               -------------------------
for Base TT System Tables, TT System Tables, TT/ST System Tables or TT/SJ System
Tables during the first [] months after the Closing Date; provided, however, (i)
if the cost of materials and equipment used in the manufacture of Base TT System
Tables, TT System Tables, TT/ST System Tables or TT/SJ System Tables supplied to
MIKN by third parties increases, MIKN may increase the price charged to HOC for
such items, but not by more than the actual increase in such costs to MIKN; and
(ii) MIKN may increase HOC's prices for each of a Base TT System Table, TT
System Table, TT/ST System Table and a TT/SJ System Table by an amount equal to
the amount directly resulting from an increase in labor or overhead incurred by
MIKN, but in no event annually more than the greater of (a) five percent (5%) or
(b) the amount of increase in the Cost

                                       13
<PAGE>

of Living Index Average For All Cities in that year over the preceding year.
Following such [] period, MIKN may increase prices on any Base TT System Tables,
TT System Tables, TT/ST System Tables or TT/SJ System Tables subject to Section
7.4.

          7.5.2 Service and Maintenance. During the first [] after the Closing
                -----------------------
Date, MIKN shall not increase its fees to be paid under the Service and
Maintenance Agreements. After such [] period, such monthly service and
maintenance fees may not be increased by more than [] annually.

8.   LICENSE FEES AND ROYALTIES TO HOC

     8.1  License Fees. In consideration of HOC's obligations hereunder and of
          ------------
the licenses granted under the License Agreement, MIKN agrees to pay HOC the
following license fees.

          8.1.1 Initial License Fee. Upon the Closing Date, MIKN shall pay HOC
                -------------------
an initial license fee ("Initial License Fee") of [    ] payable in
                         -------------------
unregistered MIKN Shares. The share price for determining the number of MIKN
Shares deliverable to HOC shall be the Initial Market Price.


          8.1.2 Additional License Fee. If HOC installs in HOC Properties the
                ----------------------
Minimum, HOC shall be eligible to receive an additional license fee ("Additional
                                                                      ----------
License Fee") of up to [] payable in MIKN Shares. The share price for
-----------
determining the number of MIKN Shares deliverable to HOC as the Additional
License Fee shall be the lower of (i) the Initial Market Price, and (ii) the
average of the high and low price of MIKN Shares on the NASDAQ National Market
System on the last trading day immediately prior to the date the Additional
License Fee, or any installment thereof, becomes payable. The Minimum may be
referred to as HOC's "Initial Installed Base Commitment".
                      ---------------------------------

          The Additional License Fee shall be payable quarterly in arrears in
the amount of [] worth of MIKN Shares for each Quota (as defined below) of
Points (as defined below) achieved by HOC for the prior fiscal quarter. HOC
shall earn [] "Point" per installation of a TT/ST System Table or TT/SJ System
Table and [] Point per installation of a Base TT System Table or a TT System
Table. "Quota" shall be calculated in accordance with the following formula: []

          8.1.3 Bonus License Fee. If HOC achieves a total of [] Points within
                -----------------
[] after the Minimum Date, HOC shall become eligible to receive a bonus license
fee ("Bonus License Fee") of [] worth of MIKN Shares, upon the condition
      -----------------
precedent that HOC installs an additional [] or more TT/ST System Tables and
TT/SJ System Tables in HOC Properties within twelve (12) months thereafter. The
share price for determining the number of MIKN Shares deliverable to HOC shall
be the lower of: (i) the Initial Market Price; or (ii) the average of the high
and low price of MIKN Shares on the NASDAQ National Market System on the day the
Bonus License Fee becomes payable.

          8.1.4 Adjustment Upon Common Stock Event. Subsequent to the Closing
                ----------------------------------
Date, upon the happening of a Common Stock Event (as hereinafter defined), the
Initial Market Price

                                       14
<PAGE>

shall, simultaneously with the happening of such Common Stock Event, be adjusted
by multiplying the Initial Market Price in effect immediately prior to such
Common Stock Event by a fraction (i) the numerator of which shall be the number
of MIKON Shares issued and outstanding immediately prior to such Common Stock
Event, and (ii) the denominator of which shall be the number of MIKN Shares
issued and outstanding immediately after such Common Stock Event, and the
product so obtained shall thereafter be the Initial Market Price. The Initial
Market Price shall be readjusted in the same manner upon the happening of each
subsequent Common Stock Event. As used herein, the term "Common Stock Event"
shall mean (i) the issuance by MIKN of additional MIKN Shares as a dividend or
other distribution on the outstanding MIKN Shares, (ii) a subdivision of the
outstanding Shares into a greater number of MIKN Shares, or (iii) a combination
of the outstanding MIKN Shares into a smaller number of MIKN Shares, whether
effected through a stock dividend, stock split, reverse stock split or
otherwise.

         8.1.5 Adjustment for Reclassification, Exchange and Substitution. If
               ----------------------------------------------------------
at any time or from time to time after the Closing Date the MIKN Shares are
changed into the same or a different number of shares of any class or classes of
stock, whether by recapitalization, reclassification or otherwise (other than by
                                                                   ----- ----
a Common Stock Event provided for elsewhere in this Section 8), then appropriate
adjustment shall be made to the Initial Market Price to reflect the occurrence
of such recapitalization, reclassification or other event.

     8.2 Royalties. MIKN shall pay HOC a royalty of [] for any other system
         ---------
utilizing the TT System Intellectual Property Rights (as defined in Section 1.11
of the License Agreement) sold or leased by MIKN to any party other than to a
HOC Property. MIKN shall further pay HOC a royalty of [] for all TT/ST System
Tables or TT/SJ System Tables for which MIKN provides maintenance services to a
HOC Property pursuant to a Service and Maintenance Agreement. After expiration
of the last to expire of the Licensed Patents, the preceding royalties shall be
reduced to [] per Base TT System Table, TT System Table, TT/SJ System Table or
TT/ST System Table and [] per table per month for TT/ST System Tables or TT/SJ
System Tables for which MIKN provides maintenance services.

     8.3 Records and Royalty Reports. MIKN shall keep accurate records of its
         ---------------------------
operations respecting the manufacture and sale, lease or other transfer of the
Base TT Systems, TT Systems, TT/ST Systems and the TT/SJ Systems to the extent
necessary for the royalties and fees payable hereunder to be determined,
including records of the quantity and price of such Systems. MIKN shall prepare
quarterly written reports of the same, disclosing the quantity of such Systems
sold, leased or otherwise transferred by MIKN and showing the amount of
royalties due for such quarter, and shall promptly submit such reports to HOC
within thirty (30) days after the end of each quarter, along with the required
royalty payment. Such reports shall be certified as true, correct and complete
by the Chief Financial Officer of MIKN.

     8.4 Audit. Upon reasonable notice, HOC shall have the right to examine
         -----
MIKN's records relating to sales of the Base TT Systems, the TT Systems, the
TT/ST Systems and the TT/SJ Systems through an independent representative during
ordinary business hours to the extent necessary to confirm or correct such
reports. Such inspections shall be made by a mutually agreeable representative,
which representative may furnish to HOC its conclusions as to the accuracy of
such reports, as to any discrepancies therein, and as to any adjustment
necessary

                                       15
<PAGE>

to be made to provide for payment of the proper amount of royalties. In the
event that any examination by such mutually agreeable representative reveals
that MIKN has underpaid royalties and fees due to HOC by five percent (5%) or
more, MIKN shall pay to HOC within five (5) business days of the receipt of
written notice by HOC of MIKN's underpayment the full expense of said
examination and any additional royalties and fees due; otherwise the costs of
such representative shall be paid for by HOC. In addition, in the event of
underpaying by MIKN, MIKN shall pay a late fee in the amount of the lesser of
one percent (1%) per month or the highest rate allowed by laws of the amount
underpaid.

     8.5 Maintenance of Records. MIKN shall maintain all records relating to the
         ----------------------
manufacture, sale, lease or other transfer of the Base TT Systems, TT Systems,
TT/ST Systems, and the TT/SJ Systems during the term of this Master Agreement
and for a period of five (5) years thereafter.

9.   REGISTRATION RIGHTS

     Upon the Closing Date, MIKN and HOC will execute a Registration Rights
Agreement in the form set forth in Exhibit C hereto.

10.  TERM AND TERMINATION

     10.1 Term. Unless earlier terminated in accordance with its terms, this
          ----
Master Agreement shall extend until the expiration date of the License
Agreement.

     10.2 Events of Default by MIKN. The occurrence of any of the following
          -------------------------
events will constitute an "Event of Default by MIKN":

          (a) a material adverse change in the financial condition of MIKN and
its consolidated subsidiaries, taken as a whole, that can be reasonably expected
to render or prospectively render MIKN incapable of complying with its
obligations under this Agreement, the License Agreement, the escrow agreement
attached to the License Agreement as Exhibit B, any or all of the Service and
Maintenance Agreements or the Registration Rights Agreement, such change to be
measured from the Closing Date; or

          (b) MIKN defaults in any material respect under this Agreement, the
License Agreement, the escrow agreement attached as Exhibit B to the License
Agreement, the Registration Rights Agreement or any of the Service and
Maintenance Agreements, and such default is not cured by MIKN within the
appropriate cure period stated in the relevant Agreement, or if no cure period
is stated, thirty (30) days after HOC gives MIKN written notice of such default
or violation; or

          (c) MIKN or any of its Affiliates becomes insolvent, or admits in
writing its inability to pay its debts as they mature, or makes an assignment
for the benefit of creditors, or applies for or consents to the appointment of a
receiver, liquidator, custodian or trustee for it or

                                       16
<PAGE>

for a substantial part of its property or business, or such a receiver,
liquidator, custodian, or trustee otherwise is appointed; or

          (d) Bankruptcy, insolvency, reorganization or liquidation proceedings
or other proceedings for relief under any bankruptcy law or any law for the
relief of debtors are instituted by or against MIKN or any of its Affiliates,
(that, with respect to such Affiliate(s), can be reasonably expected to render
or prospectively render MIKN incapable of complying with its obligations under
this Agreement, the License Agreement, the escrow agreement attached to the
License Agreement as Exhibit B, any or all of the Service and Maintenance
Agreements or the Registration Rights Agreement), or any order, judgment or
decree is entered against MIKN or any such Affiliate decreeing its dissolution;
provided, however, that with respect to an involuntary petition in bankruptcy,
-----------------
such petition has not been dismissed within thirty (30) days after the filing of
such petition; or

          (e) This Agreement or the Registration Rights Agreement, the License
Agreement, the escrow agreement attached to the License Agreement as Exhibit B,
or any of the Service and Maintenance Agreements for any reason (other than the
satisfaction in full by MIKN of all its obligations to HOC) cease to be, or are
asserted by MIKN not to be, legal, valid and binding obligations of MIKN,
enforceable in accordance with their terms, and such occurrence has not been
cured within ten (10) days after HOC becomes aware thereof.

     10.3 Remedies of HOC upon Event of Default by MIKN. Except for the
          ---------------------------------------------
occurrence of an Event of Default which is also an Arbitrable Matter, which must
be arbitrated prior to HOC exercising its rights under this Section 10.3, upon
an Event of Default by MIKN, at HOC's sole option by written notice to MIKN, HOC
may do any one or more of the following:

          (a) Exercise all rights and remedies granted under this Agreement, the
Registration Rights Agreement, the License Agreement and the Service and
Maintenance Agreements, or otherwise available at law or in equity; and/or

          (b) Terminate this Agreement and/or the License Agreement and/or any
Service and Maintenance Agreements between MIKN and a HOC Property (as defined
in the Master Agreement).

     10.4 Events of Default by HOC. The occurrence of any of the following
          ------------------------
events will constitute an "Event of Default by HOC":
                           -----------------------

          (a) HOC materially defaults under this Agreement (other than HOC's
failure to purchase the Minimum), and such default is not cured by HOC within
thirty (30) days after MIKN gives HOC written notice of such default; or

          (b) HOC becomes insolvent, or admits in writing its inability to pay
its debts as they mature, or makes an assignment for the benefit of creditors,
or applies for or consents to the appointment of a receiver, liquidator,
custodian or trustee for it or for a substantial part of its property or
business, or such a receiver, liquidator, custodian or trustee otherwise is
appointed; or

                                       17
<PAGE>

          (c) Bankruptcy, insolvency, reorganization or liquidation proceedings
or other proceedings for relief under any bankruptcy law or any law for the
relief of debtors are instituted by or against HOC, or any order, judgment or
decree is entered against HOC decreeing its dissolution; provided, however, that
                                                         -----------------
with respect to an involuntary petition in bankruptcy, such petition has not
been dismissed within thirty (30) days after the filing of such petition; or

          (d) This Agreement or the Registration Rights Agreement, the License
Agreement, the escrow agreement attached to the License Agreement as Exhibit B,
or any of the Service and Maintenance Agreements for any reason (other than the
satisfaction in full by HOC of all of its obligations to MIKN) cease to be, or
are asserted by HOC not to be legal, valid and binding obligations of HOC,
enforceable in accordance with their terms, and such occurrence has not been
cured within ten (10) days after MIKN becomes aware thereof.

     10.5 Remedies of MIKN upon Event of Default by HOC. Except for the
          ---------------------------------------------
occurrence of an Event of Default which is also an Arbitrable Matter, which must
be arbitrated prior to MIKN exercising its rights under this Section 10.5, upon
an Event of Default by HOC, at MIKN's sole option by written notice to HOC, MIKN
may do any one or more of the following:

          (a) Exercise all rights and remedies available under this Agreement,
the License Agreement, the Service and Maintenance Agreements and at law or in
equity; and/or

          (b) Terminate this Agreement and the License Agreement.

     10.6 Effect of Termination or Expiration.
          -----------------------------------

          10.6.1 Termination of Other Agreements. Termination of this Master
                 -------------------------------
Agreement under Section 10.5 (b) shall automatically terminate the License
Agreement. Termination of this Master Agreement by HOC upon the occurrence of an
Event of Default by MIKN shall entitle HOC, at its option, to terminate at any
time one or more of any Service and Maintenance Agreements in effect between
MIKN and a HOC Property.

          10.6.2 Payments Due. Upon termination or expiration, either party
                 ------------
will, within ten (10) days thereafter, pay the other party any and all payments
and interest due and outstanding as of the date of such termination or
expiration.

          10.6.3 Remaining Inventory. Upon termination of this Master Agreement
                 -------------------
for cause or without cause, MIKN shall have [] to distribute any remaining
inventory in process and in existence as of the effective date of the
termination, subject to the obligation for MIKN to pay royalties hereunder for
any such distribution.

          10.6.4 Liability for Termination. EXCEPT FOR DIRECT DAMAGES RESULTING
                 -------------------------
FROM A BREACH OF THE TERMS OF THIS MASTER AGREEMENT, NEITHER PARTY SHALL BE
LIABLE TO THE OTHER FOR DAMAGES OF ANY SORT AS A RESULT OF TERMINATING THIS
MASTER AGREEMENT IN ACCORDANCE WITH THE TERMS OF THIS MASTER AGREEMENT.

          10.6.5 Survival. The parties acknowledge and agree that Sections 1,
                 --------
4.3, 8, 10,

                                       18
<PAGE>

11, 12, 13 and 15 of this Master Agreement shall survive termination or
expiration.

11.  ARBITRATION

     11.1 Arbitrable Matters. The parties agree to submit to final and binding
          ------------------
arbitration, pursuant to the conditions of this Article 11, in Las Vegas, NV at
a location specified by the party seeking such arbitration, disputes to the
extent they constitute the following ("Arbitrable Matters"):
                                       ---------- -------

     (a) whether a modification to the Final TT Specifications materially
increases the cost to MIKN to develop or manufacture the TT System, and, if so,
the amount of appropriate adjustments to the prices HOC shall pay for the TT
System hereunder pursuant to Section 2.1;

     (b) whether an Event of Default has occurred within the meaning of Section
10.2(a);

     (c) whether an Event of Default has occurred within the meaning of Section
10.2(b) or 10.4(a), as applicable, with respect to performance of a party's
obligations under Sections 2.1, 2.2, 2.2.1, 2.3, 2.4, 2.5, 2.6, 3 and 5 and, if
so, the amount of damages caused to the non-defaulting party by virtue of such
Event of Default;

     (d) the computation of the License Fees or royalties due hereunder,
including any adjustments to the Initial Market Price as provided in Section
8.1.5;

     (e) whether a party has devoted Substantially Equivalent Resources where
required hereunder and, if not, the amount of damages caused to the other party
as a result thereof;

     (f) whether the Base TT System, TT System, TT/ST System or the TT/SJ System
conforms to the Preliminary TT Specifications, the Final TT Specifications the
TT/ST Specifications and the TT/SJ Specifications, respectively; and, if not,
the amount of damages caused to HOC as a result thereof; and

     (g) the amount, if any, of price adjustments permitted or required to be
made, as applicable, pursuant to the provisions of Section 7.5.1.

     11.2 Arbitration Process.
          -------------------

     (a) The Arbitrators. Any arbitration proceeding shall be conducted by three
         ---------------
(3) arbitrators (the "Arbitrators") and the decision of the Arbitrators shall be
                      -----------
binding on all parties. Each Arbitrator shall have expert competence in
accounting matters as to Arbitrable Matters (b), (d), (e) and (g) and in
technology matters as to all other Arbitrable Matters. The party desiring to
submit any matter relating to the Arbitrable Matters to arbitration shall do so
by written notice to the other party, which notice shall set forth the items to
be arbitrated, such party's choice of an Arbitrator, and such party's
substantive position in the arbitration. The party receiving such notice shall,
within fifteen (15) days (except for Arbitrable Matter (b) above, in which case
the time shall be reduced to five (5) days), after receipt of such notice,
appoint an Arbitrator and notify the other party of its appointment and of its
substantive position. The Arbitrators

                                       19
<PAGE>

appointed by the parties to the Arbitration shall select an additional
arbitrator meeting the aforedescribed criteria. The Arbitrators shall be
required to render a decision in accordance with the procedures set forth in
Subparagraph (b) below within thirty (30) days after being notified of their
selection (except for Arbitrable Matter (b) above, in which event the time
period shall be reduced to five (5) days).

     (b) Arbitration Procedures. Arbitration shall be conducted in accordance
         ----------------------
with the Uniform Arbitration Act, except to the extent the provisions of such
Act are modified by this Agreement or the subsequent mutual agreement of the
parties. In all arbitration proceedings, the Arbitrators shall be required to
agree upon and approve the substantive position advanced by a party with respect
to each disputed item, except as to the question of the amount of damages caused
to a non-defaulting party. Failure of the Arbitrators to do so shall render the
arbitration void and the party who requested such arbitration may avail itself
of the provisions of Section 10. Judgment upon the award rendered by the
Arbitrators may be entered in any court having jurisdiction thereof. Any party
hereto may bring an action, including a summary or expedited proceeding, to
compel arbitration of any controversy or claim to which this provision applies
in any court having jurisdiction over such action in Clark County, Nevada, and
the parties agree that jurisdiction and venue in Clark County, Nevada are
appropriate and approved by such parties.

     (c) Effect of Arbitration. Following the conclusion of arbitration, if the
         ---------------------
Arbitrators agree upon and support the substantive position advanced by the
party seeking arbitration and such position is that an Event of Default by the
other party has occurred by reason of the issue being arbitrated (the
"Prevailing Party") the Prevailing Party may avail itself of the remedies
 ----------------
provided for in Section 10 (other than instituting litigation with respect to
the disputed issues that have been arbitrated).

     (d) Matters That Are Not Arbitrable Matters. Neither party shall have any
         ---------------------------------------
obligation to arbitrate any disputes arising out of or relating to this
Agreement that are not expressly defined in this Section as Arbitrable Matters.
In addition, HOC shall have no obligation to arbitrate any action for
preliminary or other injunctive or equitable relief within the provisions of
Section 15.13 below.

12.  LIMITATION OF LIABILITY AND INDEMNITY

     12.1 Disclaimer of Certain Types of Damages. IN NO EVENT WILL MIKN OR HOC
          --------------------------------------
BE LIABLE FOR LOST PROFITS, OR ANY SPECIAL, INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, ARISING IN
ANY WAY IN CONNECTION WITH THIS MASTER AGREEMENT. THIS LIMITATION WILL APPLY
EVEN IF MIKN AND HOC HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES AND
NOTWITHSTANDING ANY FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.

     12.2 Indemnity. The following terms apply to any infringement or claim of
          ---------
infringement of any patent, trademark, copyright, trade secret, or other
proprietary interest based on the licensing, use, or sale of the TT/ST System or
TT/SJ System or the Software or Hardware of the TT/ST System or the TT/SJ System
(as those terms are defined in the Service and

                                       20
<PAGE>

Maintenance Agreements). MIKN shall indemnify HOC for any loss, damage, expense,
or liability, including costs and reasonable attorneys' fees finally awarded,
that may result by reason of any such infringement or claim, except where such
infringement or claim arises solely from MIKN's adherence to HOC's written
instructions or directions which involve the use of merchandise or items other
than (i) commercial merchandise which is available on the open market or is the
same as such merchandise; or (2) items of HOC's origin, design, or selection;
and HOC shall so indemnify MIKN in such excepted cases. Each party shall defend
or settle, at its own expense, any action or suit against the other for which it
is responsible hereunder. Each party shall notify the other promptly of any
claim of infringement for which the other is responsible, and shall cooperate
with the other in every reasonable way to facilitate the defense of any such
claim.

     12.3 Remedies. In addition, in the event an injunction or order shall be
          --------
obtained against the use of any component of the TT/ST System or TT/SJ System by
reason of any such infringement allegation or if, in MIKN's sole opinion, the
TT/ST System or TT/SJ System or any component thereof is likely to become the
subject of a claim of infringement or violation of any existing patent,
copyright, trademark, trade secret, or other proprietary right of a third party,
MIKN will, without in any way limiting the foregoing, in MIKN's sole discretion
and at MIKN's expense either (1) procure for HOC the right to continue using the
item; (2) replace or modify the item so that it becomes noninfringing, but only
if the modification or replacement does not, in HOC's reasonable opinion,
adversely affect the functional performance or specifications for the item or
its use by HOC, or (3) if neither (1) nor (2) above is practical, remove the
item from HOC and refund to HOC all fees advanced by HOC Properties under each
of the Service and Maintenance Agreements for each of the HOC Properties less a
pro rata portion for periods of use prior to removal, and release HOC from any
further liability.

13.  CONFIDENTIAL INFORMATION

     Each party agrees to keep all Confidential Information of the other party
to which it has access hereunder strictly confidential, not to use such
information except in the performance of this Master Agreement or as permitted
by the licenses granted under the License Agreement, and not to disclose any
such Confidential Information to any person or entity other than its own
employees and agents who have a need to know and who have been informed in
advance of the receiving party's obligations with respect to such Confidential
Information. Each party will use all reasonable efforts to protect such
Confidential Information from unauthorized use or disclosure, but in no event
less effort than it uses to protect its own confidential information from
unauthorized use or disclosure.

14.  FEEDBACK

     In fulfilling their obligations under this Agreement, the License
Agreement, and the Service and Maintenance Agreements, MIKN and HOC will work
cooperatively and closely with management at the HOC Properties using the Base
TT System, TT System, TT/SJ System and/or the TT/ST System and will endeavor in
good faith to minimize interference with the ongoing business of the property
and to maximize the usefulness and functionality of the Base

                                       21
<PAGE>

TT System, TT System and/or the TT/ST System and/or the TT/SJ System. The
parties acknowledge that this may require regular surveys of the users of the
Base TT System, TT System and/or the TT/ST System and/or the TT/SJ System and
meetings between representatives of the HOC Properties, HOC and MIKN.

15.  GENERAL

     15.1 Entire Agreement. This Master Agreement and its Exhibits, together
          ----------------
with the License Agreement, the Registration Rights Agreement and the various
Service and Maintenance Agreements, constitute the complete agreement of the
parties and supersede any other agreements, written or oral, concerning the
subject matter hereof.

     15.2 Succession and Assignment. Neither party may assign or delegate any of
          -------------------------
its rights or obligations hereunder without the other party's prior written
consent, and any assignment or delegation without such consent shall be void;
provided, that the rights and obligations of HOC under this Master Agreement may
be assigned and delegated by HOC (i) by operation of law, (ii) to a wholly-owned
subsidiary of HOC, and/or (iii) to anyone acquiring all or substantially all of
the assets or stock of HOC. Subject to the foregoing sentence, the terms and
conditions of this Master Agreement will inure to the benefit of and be binding
upon the respective successors and assigns of the parties.

     15.3 Notices. Any notice required or permitted under this Master Agreement
          -------
will be given in writing and will be deemed effectively given (i) upon personal
delivery; (ii) upon transmission by facsimile; (iii) three (3) business days
following deposit in the United States mail, by certified or registered mail,
return receipt requested, postage prepaid; or (iv) one (1) business day after
being dispatched via nationally recognized overnight express courier. Each
party's address for notice under this Master Agreement will be:

          To MIKN:                            To HOC:
          -------                             ------
          Mikohn Gaming Corporation           Harrah's Operating Company, Inc.
          1045 Palms Airport Drive            1023 Cherry Road
          Las Vegas, NV  89119                Memphis, TN 38117
          Attn:  Charles McCrea, Esq.         Attn: Messrs. John Boushy and
          Fax No.: (702) 263-1695             John McConomy, Esq.
                                              Fax No.: (901) 762-8914

                                              with a copy to:

                                              David L. Hayes, Esq.
                                              Fenwick & West LLP
                                              Two Palo Alto Square
                                              Palo Alto, CA 94306
                                              Fax No.: (650) 494-1417

     15.4 Governing Law. This Master Agreement shall be governed and construed
          -------------
in accordance with the laws of the State of Nevada, without reference to or
application of its

                                       22
<PAGE>

conflicts of law principles.

     15.5 No Agency. Neither party is to be construed as the agent, partner, or
          ---------
joint venturer or to be acting as the agent, partner or joint venturer of the
other party hereunder in any respect.

     15.6 Multiple Counterparts. This Master Agreement may be executed in
          ---------------------
several counterparts, all of which taken together shall constitute one single
Master Agreement between the parties.

     15.7 Modification; Waiver. No waiver , consent or amendment with respect to
          --------------------
this Master Agreement will be binding unless it is set forth in writing and
signed by both of the parties thereto. No course of dealing between MIKN and HOC
will operate as a waiver or modification of any party's rights under this Master
Agreement. No delay or failure on the part of either party in exercising any
right or remedy under this Master Agreement will operate as a waiver of such
right or any other right. A waiver given on one occasion will not be construed
as a bar to, or as a waiver of, any right or remedy on any future occasion.

     15.8 Severability. If any one or more of the provisions of this Master
          ------------
Agreement shall be held to be invalid, illegal or unenforceable, the validity,
legality or enforceability of the remaining provisions of this Master Agreement
shall not in any way be affected or impaired thereby.

     15.9 Amendments in Writing. Any amendment to this Master Agreement shall be
          ---------------------
in writing and signed by both parties hereto.

     15.10 Interpretation. Since this Master Agreement was prepared by both
           --------------
parties hereto, it shall not be construed against any one party as the drafting
party.

     15.11 Force Majeure. With the exception of the obligation to pay monies due
           -------------
and owing, each party hereto shall be excused from performance hereunder for any
period and to the extent that it is prevented from performing any services
pursuant hereto, in whole or in part, as a result of delays caused by the other
party or an act of God, war, civil disturbance, court order, governmental action
or inaction, laws, orders, regulations, directions or requests, or as a result
of events such as acts of public enemies, earthquakes, fires, floods, strikes or
other labor disturbances of the other party or any third party, or other cause
beyond its reasonable control and which it could not have prevented by
reasonable precautions, and such nonperformance shall not be a default hereunder
or a ground for termination hereof.

     15.12 Compliance with Laws. Both parties will comply with all laws and
           --------------------
regulations applicable to their respective activities under this Master
Agreement.

     15.13 Equitable Relief. Due to the proprietary and sensitive nature of this
           ----------------
Master Agreement, HOC will be entitled to preliminary or other injunctive or
equitable relief to remedy any actual or threatened dispute arising from any
actions in breach of any of obligations under this Master Agreement.

     15.14 Rights and Remedies Cumulative. The rights and remedies herein
           ------------------------------
provided will

                                       23
<PAGE>

be cumulative and not exclusive of any other rights or remedies provided by law
or otherwise.

     15.15 Attorney's Fees and Court Costs. In the event of any litigation or
           -------------------------------
arbitration arising out of or relating to this Agreement, the prevailing party
in such litigation or arbitration shall be entitled to its reasonable attorney's
fees and to its court costs.

     15.16 Press Release, Advertising. Neither party shall use the other's name,
           --------------------------
trademarks, service marks, or tradenames in any advertising, promotion or
publicity without the prior written permission of HOC. Neither party shall issue
any press release concerning the matters contemplated by this Agreement without
the prior written consent of the other party, except as may be required by law
or regulation. The parties agree that the press release(s) in the form attached
as Exhibit H will be issued on or after the Closing Date.

     IN WITNESS WHEREOF, the authorized representatives of the parties hereto
have signed this Master Agreement as of the date and year last set forth below.

HOC:                                        MIKN:

By:________________________________         By:________________________________

Name:______________________________         Name:______________________________

Title:_______________________________       Title:_____________________________

                                       24