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                                                                   EXHIBIT 10-SS




                                LEASE AGREEMENT

                                    between

                          EL CAMINO OFFICE INVESTMENTS

                                      and

                                  Intellicorp

                                      for

                      1975 El Camino Real West, Suite 101
                            Mountain View, Ca 94040





                                                          Dated: March 17, 1998



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1. PARTIES. This Lease dated March 17, 1998 for reference purposes only, by and
between EL CAMINO OFFICE INVESTMENTS, ("Landlord") and INTELLICORP INC., who
agree as follows:

2. PREMISES. Landlord leases to Tenant, and Tenant leases from Landlord the
office space located in Mountain View, California, 94040, described as 1975 El
Camino Real, outlined in Exhibit "A" ("Premises"). Premises have an agreed area
of approximately 34,291 rentable square feet.

3. TERM. The term of this Lease shall be for Five (5) Years, commencing on
September 1, 1998 and ending on August 31, 2003.

4.  RENT.

4.1.   Tenant shall pay to Landlord as rent for the
Premises, without demand, deduction, or off-set, the sum of One Hundred Two
Thousand Eight Hundred Seventy Three Dollars and no/100 ($102,873.00) on or
before the first day of each and every month of the term of this Lease, the
first monthly payment to be made concurrently with the execution hereof. If the
commencement date is not the first day of a month or if the Lease termination
date is not the last day of a month, the rent payable hereunder shall be
prorated, based upon a thirty day month, at the current rate for the fractional
month during which this Lease commences and/or terminates. Any rent payable for
a partial month directly following the commencement date shall be payable on the
first day of the first full calendar month of the term. Rent shall be paid to
Landmark Investments, Limited, at 2093 Landings Drive, Mountain View, CA 94043.

4.2. The base rent provided for in 4.1. above shall increase three percent (3%)
each year on the anniversary date of the commencement of the term of the Lease
stated in 3. above.

4.3.  Late Charges.  Tenant hereby acknowledges that late
payment by Tenant to Landlord of rent or other sums due

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hereunder will cause Landlord to incur costs not contemplated by this Lease, the
exact amount of which will be extremely difficult to ascertain. Such costs
include, but are not limited to, processing and accounting charges, and late
charges which may be imposed upon Landlord by terms of any mortgage or trust
deed covering the Premises. Accordingly, if any installment of rent or of a sum
due from Tenant shall not be received by Landlord or Landlord's designees by
12:00 noon on the fifth (5th) day of each month of the term hereof, then Tenant
shall pay to Landlord a late charge equal to five percent (5%) of such overdue
amount. The parties hereby agree that such late charges represent a fair and
reasonable estimate of the cost that Landlord will incur by reason of the late
payment by Tenant. Acceptance of such late charges by the Landlord shall in no
event constitute a waiver of Tenant's default with respect to such overdue
amount, nor prevent Landlord from exercising any of the other rights and
remedies granted hereunder.

5.  SECURITY DEPOSIT.  On execution of this Lease, Tenant
shall deposit with Landlord an additional $49,873.00 for a total security
deposit of $102,873.00 for the performance by Tenant of the provisions of this
Lease. If Tenant is in default, Landlord can use the security deposit, or any
portion of it, to cure the default or to compensate Landlord for all damage
sustained by Landlord resulting from Tenant's default. Tenant shall immediately
on demand pay to Landlord a sum equal to the portion of the security deposit
expended or applied by Landlord as provided in this paragraph so as to maintain
the security deposit in the sum initially deposited with Landlord. If Tenant is
not in default at the expiration or termination of this Lease, Landlord shall,
no later than fourteen (14) days after lease expiration or termination, return
to Tenant (or at Landlord's option, to the last assignee of Tenant's interest
hereunder), the balance of the security deposit. Landlord shall not be required
to keep this security deposit separate from its general funds, and Tenant shall
not be entitled to interest on such deposit.

6.  POSSESSION.

6.1. If Landlord, for any reason cannot deliver possession of the Premises to
Tenant at the commencement of the term hereof, this Lease shall not be void or
voidable nor shall Landlord be liable to Tenant for any loss or damage 


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resulting therefrom, nor shall the expiration date of the above term be
extended, but, in that event, all rent shall be abated during the period between
the commencement of said term and the time when Landlord delivers possession.

6.2. In the event that Landlord shall permit Tenant to occupy the Premises prior
to the commencement date of the term, such occupancy shall be subject to all of
the provisions of this Lease and said early possession shall not advance the
termination date hereinabove provided. Rent shall be prorated and prepaid for
early occupancy at the current rate.

7.  USE.

7.1 Use. The Premises shall be used and occupied by Tenant for general office
purposes and for no other purpose without the prior written consent of the
Landlord.

7.2  Uses Prohibited.
a. Tenant shall not do or permit anything to be done in or about the Premises
nor bring or keep anything therein which will increase the existing rate or
affect any fire or other insurance upon the building or any of its contents, or
cause a cancellation of any insurance policy covering said building or any part
thereof or any of its contents, nor shall Tenant sell or permit to be kept used
or sold in or about said Premises any articles or substances, inflammable or
otherwise, which may be prohibited by a standard form policy of fire insurance.

b. Tenant shall not do or permit anything to be done in or about the Premises
which will in any way obstruct or interfere with the rights of other tenants of
the building or injure or annoy them or use or allow the Premises to be used for
any unlawful or objectionable purpose.

c. Tenant shall not use the Premises or permit anything to be done in or about
the Premises which will in any way conflict with any law now in force or which
may hereafter be enacted. Tenant shall at its cost promptly comply with all laws
now in force or which may hereafter be in force and with the requirements of any
board of fire underwriters or other similar body relating to Tenant's
improvements or acts.


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8. ALTERATIONS AND ADDITIONS. Landlord and its agents, contractors and employees
shall make all alterations and additions to the Premises. Tenant shall not make
or allow any alterations, additions or improvements of or to the Premises. Any
such alterations, additions or improvements, including, but not limited to,
wallcovering, paneling and built-in cabinet work, but excepting movable
furniture and trade fixtures, shall become a part of the realty, shall belong to
the Landlord and shall be surrendered with the Premises at expiration or
termination of the Lease. If Landlord consents to construct any alterations,
additions or improvements requested by Tenant, they shall be made at Tenant's
cost. Upon termination Tenant shall, upon written demand by Landlord promptly
pay Landlord to remove any alterations, additions or improvements requested by
Tenant. Such removal and repair of any damage to the premises caused by such
removal shall be at Tenant's cost. Tenant shall approve in writing the fixed
cost of any Tenant requested work prior to Landlord commencing work.

9. LIENS. Tenant shall keep the Premises and the property in which the Premises
are situated free from any liens arising out of any work performed, materials
furnished or obligations incurred by Tenant. Landlord may require Tenant to
provide Landlord, at Tenant's cost, a lien and completion
bond in an amount equal to one and one-half (1-1/2) times the estimated cost of
any improvements, additions, or alterations by Tenant, to insure Landlord
against liability for mechanic's and materialmen's liens and to insure
completion for the work.

10. REPAIRS AND MAINTENANCE. By taking possession of the Premises, Tenant shall
be deemed to have accepted the Premises as being in good sanitary order,
condition and repair. Tenant shall at Tenant's cost, keep the premises and every
part thereof in good condition and repair except for damages from causes beyond
the control of Tenant and ordinary wear and tear. Tenant shall upon the
expiration or sooner termination of this Lease surrender the Premises to the
Landlord in good condition, ordinary wear and tear and damage from causes beyond
the reasonable control of the Tenant excepted. Unless specifically provided in
an addendum to this Lease, Landlord shall have no obligation to alter, remodel,
improve, repair, decorate or paint the Premises or any part thereof and the
parties hereto affirm 


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that Landlord has made no representations to Tenant respecting the condition of
the premises or the building except as specifically herein set forth.
Notwithstanding the above provisions, Landlord shall repair and maintain the
structural portions of the building, including the exterior walls and roof of
the building, the standard plumbing, air conditioning, heating and electrical
systems furnished by Landlord, unless such maintenance and repairs are caused in
part or in whole by the act, neglect, fault or mission of any duty by the
Tenant, its agents, employees or invitees, in which case Tenant shall pay to
Landlord the reasonable cost of such maintenance and repairs. Tenant shall give
Landlord written notice of any required repairs or maintenance. Landlord shall
not be liable for any failure to repair or to perform any maintenance unless
such failure shall persist for an unreasonable time after written notice. Any
repairs or maintenance to supplemental cooling equipment required for Tenant's
special needs are the responsibility of Tenant. Except as specifically herein
set forth, there shall be no abatement of rent and no liability of Landlord by
reason of any injury to or interference with Tenant's business arising from the
making of any repairs, alterations or improvements to any portion of the
building or the Premises or to fixtures, appurtenances and equipment therein.
Tenant waives the right to make repairs at Landlord's expense under any law,
statute or ordinance now or hereafter in effect.

11. ASSIGNMENTS AND SUBLETTING. Tenant shall not, voluntarily or by operation of
law, assign, transfer, or encumber its interest under this Lease or in the
Premises nor sublease all or any part of the premises or allow any other person
or entity (except Tenant's employees, agents and invitees) to occupy or use all
or any part of the premises without the prior written consent of Landlord. If
the assignment or subletting is at a higher rent than Tenant is paying Landlord
for the assigned or sublet portion of the Premises then the Tenant shall pay
Landlord seventy-five (75%) of the difference as received. All costs of
assigning or subletting shall be borne by Tenant. Any consent by Landlord shall
not release Tenant from liability hereunder, and a consent to one assignment,
subletting, occupation or use shall not be deemed a consent to any subsequent
assignment, subletting, occupation or use. Any such purported assignment,
subletting, or permission to occupy or use without such consent from Landlord
shall be void and shall, at the option of Landlord, constitute a 




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default under this Lease. Tenant immediately and irrevocably assigns to
Landlord, as security for Tenant's obligations under this Lease, all rent from
any subletting of all or a part of the Premises as permitted by this Lease, and
Landlord, as assignee and as attorney-in-fact for Tenant, or a receiver for
Tenant appointed on Landlord's application, may collect such rent and apply it
toward Tenant's obligations under this Lease; except that, until the occurrence
of an act of default by Tenant, Tenant shall have the right to collect such
rent.

12. HOLD HARMLESS. Except as to claims based on the sole gross negligence or
willful misconduct of Landlord, its agents or employees, Tenant shall hold
Landlord harmless from any claims arising from Tenant's use of the premises or
from any activity permitted by Tenant in or about the Premises, and any claims
arising from any breach or default in Tenant's performance of any obligation
under the terms of this Lease. If any action or proceeding is brought by reason
of any such claim in which Landlord is named as a party, Tenant shall defend
Landlord therein at Tenant's expense by counsel reasonably satisfactory to
Landlord. Landlord and its agents shall not be liable for any damage to property
entrusted to employees of the building, nor for loss or damage to any property
by theft or otherwise, nor from any injury to or damage to persons or property
resulting from any cause whatsoever, unless caused by or due to the sole gross
negligence or willful misconduct of Landlord, its agents, or employees. Landlord
shall not be liable for any latent defect in the Premises or in the building of
which they are a part. Tenant shall give prompt notice to Landlord in case of
fire or accidents in the Premises or in the building or of alleged defects in
the building, fixtures or equipment.

13.  INSURANCE.

13.1 Coverage. Tenant shall assume the risk of damage to any fixtures, goods,
inventory, merchandise, equipment, furniture and leasehold improvements, and
Landlord shall not be liable for injury to Tenant's business or any loss of
income therefrom relative to such damage. Tenant shall, at all times during the
term of this Lease, and at its own cost, procure and continue in force the
following insurance coverage.

a.  Commercial general liability insurance, insuring




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Landlord and Tenant against any liability arising out of the ownership, use,
occupancy or maintenance of the Premises and all areas appurtenant thereto.

13.2. Insurance Policies. The limits of said insurance policies shall not,
however, limit the liability of the Tenant hereunder. Tenant may carry said
insurance under a blanket policy, providing, however, said insurance by Tenant
shall name Landlord as an additional insured. If Tenant shall fail to procure
and maintain said insurance, Landlord may, but shall not be required to, procure
and maintain same, but at the expense of Tenant. Insurance required hereunder
shall be in companies that rate B+ or better in "Best's Insurance Guide". Tenant
shall deliver to Landlord prior to occupancy of the premises copies of policies
of
insurance required herein or certificates evidencing the existence and amounts
of such insurance with loss payable clauses, satisfactory to Landlord. No policy
shall be cancellable or subject to reduction of coverage except after fifteen
(15) days prior written notice to Landlord. The minimum acceptable amount of
comprehensive liability insurance is $1,000,000 against claims in any
occurrence, and property damage insurance in an amount of not less than $100,000
per occurrence, or combined single limit of $1,000,000 commercial liability and
property damage insurance.

13.3. Waiver of Subrogation. As long as their respective insurers so permit,
Landlord and Tenant each hereby waive any and all rights of recovery against the
other for any loss or damage occasioned to such waiving party or its property of
others under its control to the extent that such loss or damage is insured
against under any fire or extended coverage insurance policy which either may
have in force at the time of such loss or damage. Each party shall obtain any
special endorsement, if required by their insurer, to evidence compliance with
the aforementioned waiver.

14.  SERVICE AND UTILITIES.

14.1 Landlord's Obligations. Landlord agrees to furnish to the Premises
electricity for normal lighting and fractional horsepower office machines, and
elevator service. Landlord agrees to furnish to the Premises during reasonable
hours of generally recognized business days to be determined by Landlord, and
subject to the Rules and Regulations of the building, heat and air conditioning
required in Landlord's judgement for the comfortable use and occupancy of the
Premises, janitorial, and window washing Landlord 


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shall also maintain and keep lighted the common stairs, gallerias, entries and
toilet rooms in the building. Landlord shall not be liable for and Tenant shall
not be entitled to any reduction of rental by reason of Landlord's failure to
furnish any of the foregoing when such failure is caused by accident, breakage,
repairs, strikes, lockouts or other labor disturbances or labor disputes of any
character, or by any other cause, similar or dissimilar, beyond the reasonable
control of Landlord.

14.2 Tenant's Obligation. Tenant shall pay for, prior to delinquency, all
telephone and all other materials and services, not expressly required to be
paid by Landlord, which may be furnished to or used in, on or about the Premises
during the term of this Lease. Tenant will not, without the prior written
consent of Landlord and subject to any conditions which Landlord may impose, use
any apparatus or device in the Premises which will in any way increase the
amount of electricity or water usually furnished for use of the Premises as
general office space. If Tenant shall require water or electric current in
excess of that usually furnished or supplied for use of the Premises as general
office space, Tenant shall first procure the consent of Landlord. Wherever heat
generating machines or equipment are used in the Premises which affect the
temperature otherwise maintained by the air conditioning system, Landlord
reserves the right to install supplementary air conditioning units in the
Premises and the cost thereof, including the cost of installation, operation and
maintenance thereof, shall be paid by Tenant to Landlord upon demand by
Landlord. Landlord shall not be liable for Landlord's failure to furnish any of
the foregoing when such failure is caused by any cause beyond the reasonable
control of Landlord. Landlord shall not be liable under any circumstances for
loss of or injury to property, however occurring, in connection with failure to
furnish any of the foregoing.

15. PROPERTY TAXES. Tenant shall pay before delinquency, all personal property
or similar taxes levied or assessed and which become payable during the term
hereof upon all Tenant's equipment, furniture, fixtures and personal property
located in the Premises. Landlord shall pay all property taxes on the land and
building, except should the California Constitution be changed in a way that
results in a higher or lower tax on the Premises than the annual increases now a
matter of law, any such increase or decrease shall be passed through to tenant
on a prorated basis as an item separate from any CPI adjustments. Tenant shall
pay to Landlord its share of such taxes, if any, within thirty days after
delivery 

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to Tenant by Landlord of a statement in writing setting forth the amount of such
taxes.

16. RULES AND REGULATIONS. Tenant shall faithfully observe and comply with the
rules and regulations attached as Exhibit "B" to this Lease, as well as such
rules and regulations that Landlord shall from time to time promulgate. Landlord
reserves the right from time to time to make all reasonable modifications to
those rules which shall be binding to Tenant upon delivery of a copy of them to
Tenant. Landlord shall not be responsible to Tenant for the nonperformance of
any of said rules by any other tenant.

17. HOLDING OVER. If Tenant remains in possession without Landlord's consent,
after termination of the Lease, by lapse of time or otherwise, Tenant shall pay
Landlord for each day of such retention one-fifteenth (1/15th) of the amount of
the monthly rental for the last month prior to such termination and Tenant shall
also pay all costs, expenses and damages sustained by Landlord by reason of such
retention, including, without limitation, claims made by a succeeding tenant
resulting from Tenant's failure to surrender the Premises.

18. ENTRY BY LANDLORD. Landlord reserves the right to enter the premises at any
time to inspect the Premises, to provide any service for which Landlord is
obligated hereunder, to submit the Premises to prospective purchasers or
tenants, to post notices of nonresponsibility, and to alter, improve, maintain
or repair the Premises or any portion of the building of which the Premises are
a part that Landlord deems necessary or desirable, all without abatement of
rent. Landlord may erect scaffolding and other necessary structures where
reasonably required by the character of the work to be performed, but shall not
block entrance to the Premises and not interfere with Tenant's business, except
as reasonably required for the particular activity by Landlord. Landlord shall
not be liable in any manner for any inconvenience, disturbance, loss of
business, nuisance, interference with quiet enjoyment, or other damage arising
out of Landlord's entry on the Premises as provided in this paragraph, except
damage, if any, resulting from the negligence or willful misconduct of Landlord
or its authorized representative. Landlord shall retain a key with which to
unlock all doors into, within and about the Premises, excluding Tenant's vaults,
safes and files. In an emergency, Landlord shall have the right to use any means
which Landlord deems reasonably necessary to obtain entry to the Premises,
without liability to Tenant, except for any failure to exercise 







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due care for Tenant's property. Any such entry to the Premises by Landlord shall
not be construed or deemed to be forcible or unlawful entry into or a detainer
of the Premises or an eviction of Tenant from the Premises or any portion
thereof.

19. RECONSTRUCTION. If the Premises or the building of which the Premises are a
part are damaged by fire or other peril covered by extended coverage insurance,
Landlord agrees to make repairs and restorations to the extent and in the manner
possible at a cost not exceeding the proceeds of the insurance received by
Landlord. If the cost of repair and restoration exceeds the amount of proceeds
received from insurance, Landlord may elect to terminate this Lease by giving
notice to Tenant within twenty (20) days after determining that the cost will
exceed such proceeds.
If Landlord proceeds with repair and restoration, this
Lease shall remain in full force and effect, except that Tenant shall be
entitled to a proportionate reduction of rent while such repairs are being made.
The rent reduction shall be based upon the extent to which repair and
restoration activity materially interferes with Tenant's business at the
Premises, provided, however, that if the damage was occasioned by the fault or
neglect of Tenant, its agents or employees, there shall not be an abatement of
rent.

20.  DEFAULT; REMEDIES.

20.1 Default. The occurrence of any of the following shall constitute a default
by Tenant:

a. Failure by Tenant to pay the rent or other monies when due, where such
failure continues for three (3) business days after written notice by Landlord
to Tenant.

b. Abandonment of the Premises by Tenant.

c. Failure by Tenant to perform any other provision of this Lease where such
failure to perform is not cured within thirty (30) days after notice has been
given to Tenant; provided, however, that if the nature of the default is such
that the same cannot reasonably be cured within said thirty (30) day period,
Tenant shall not be deemed to be in default if Tenant shall within such period
commence such cure and thereafter diligently prosecute the same to completion.

d. The making by Tenant of any general assignment or general 


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arrangement for the benefit of creditors; the filing by or against Tenant of a
petition to have Tenant adjudged a bankrupt or of a petition for reorganization
or arrangement under any law relating to bankruptcy (unless, in the case of a
petition filed against Tenant, same is dismissed within sixty (60) days; the
appointment of a trustee or receiver to take possession of substantially all of
Tenant's assets located at the Premises or of Tenant's interest in this Lease,
where possession is not restored to Tenant within thirty (30) days; or the
attachment, execution or other judicial seizure of substantially all of Tenant's
assets located at the Premises or of Tenant's interest in this Lease, where such
seizure is not discharged within thirty (30) days.

20.2 Remedies. In the event of any such default Landlord may:

a. Maintain this Lease in full force and effect and recover the rent and other
monetary charges as they become due, without terminating Tenant's right to
possession irrespective of whether Tenant shall have abandoned the Premises. In
the event Landlord elects not to terminate the Lease, Landlord shall have the
right to attempt to re-let the Premises at such rent and upon such conditions
and for such a term, and to do all acts necessary to maintain or preserve the
Premises as Landlord deems reasonable and necessary without being deemed to have
elected to terminate the Lease, including removal of all persons and property
from the Premises. Such property may be removed and stored in a public warehouse
or elsewhere at the cost of and for the account of Tenant. In the event any such
reletting occurs, this Lease shall terminate automatically upon the new tenant
taking possession of the Premises. Notwithstanding that Landlord fails to elect
to terminate the Lease initially, Landlord at any time during the term of this
Lease may elect to terminate this Lease by virtue of such previous default of
Tenant.

b. Terminate Tenant's right to possession by any lawful means, in which case
this Lease shall terminate and Tenant shall immediately surrender possession of
the Premises to Landlord. In such event Landlord shall be entitled to recover
from Tenant all damages incurred by Landlord by reason of Tenant's default,
including without limitation thereto, the following: (1) the worth at the time
of award of any unpaid rent which would have been earned at the time of such
termination; plus (2) the worth at the time of award of the amount by which the
unpaid rent which would have been earned after termination until the time the
award exceeds the amount of such rental loss that is proved could have been




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reasonably avoided; plus (3) the worth at the time of award of the amount by
which unpaid rent for the balance of the term after the time of award exceeds
the amount of such rental loss that is proved could be reasonably avoided; plus
(4) any other amount necessary to compensate Landlord for all the detriment
proximately caused by Tenant's failure to perform his obligations under this
Lease or which in the ordinary course of events would be likely to result
therefrom; plus (5) at Landlord's election, such other amounts in addition to or
in lieu of the foregoing as may be permitted from time to time by applicable
law. Upon any such re-entry Landlord shall have the right to make any reasonable
repairs, alterations or modifications to the Premises, which Landlord in its
sole discretion deems reasonable and necessary. As used in (1) above, the "worth
at the time of award" is computed by allowing interest at the rate of ten
percent (10%) per annum from the date of default. As used in (2) and (3) above,
the "worth at the time of award" is computed by discounting such amount at the
discount rate of the U.S.
Federal Reserve Bank at the time of award plus one percent (1%).

Remedies of Landlord contained in this Lease shall be construed and held to be
cumulative, and Landlord shall have the right to pursue any one or all of such
remedies or any other remedy or relief which may be provided by law. No waiver
of any default of Tenant hereunder shall be implied from any acceptance by
Landlord of any rent or other payments due hereunder or any omission by Landlord
to take any action on account of such default if such default persists or is
repeated, and no express waiver shall affect defaults other than as specified in
said waiver. The consent or approval of Landlord to or of any act by Tenant
requiring Landlord's consent or approval shall not be deemed to waive or render
unnecessary Landlord's consent or approval to or of any subsequent similar acts
by Tenant.

21. EMINENT DOMAIN. If more than twenty-five percent (25%) of the Premises is
taken or appropriated by any public or quasi-public authority under powers of
eminent domain, either party hereto shall have the right at its option, to
terminate this Lease. If less than twenty-five percent (25%) of the Premises is
taken (or neither party elects to terminate as above, provided if more than
twenty-five percent (25%) is taken), the Lease shall continue, but the rental
thereafter to be paid shall be equitably reduced. If any part of the building of
which the Premises are a part is so taken or appropriated, whether or not any
part of the Premises is involved, Landlord shall be entitled to the entire 






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award and compensation for the taking which is paid or made by the public or
quasi-public agency, and Tenant shall have no claim against said award.

22. STATEMENT TO LENDER. Tenant shall at any time and from time to time, upon
not less than ten (10) days prior written notice from Landlord, execute,
acknowledge, and deliver to Landlord a statement in writing, (a) certifying that
this Lease is unmodified and in full force and effect (or, if modified, stating
the nature of such modifications and certifying that this Lease as so modified,
is in full force and effect), and the date to which the rental and other charges
are paid in advance, if any, and (b) acknowledging that there are not, to
Tenant's knowledge, any uncured defaults on the part of the Landlord hereunder,
or specifying such defaults if any are claimed and (c) certifying such other
matters as may be reasonably required by Landlord. Any such statement may be
relied upon by any prospective purchaser or encumbrancer of all or any portion
of the real property of which the Premises are a part.

23. PARKING. Tenant shall have the right to use, in common with the other
tenants, occupants or vistors of the building, parking facilities, provided by
Landlord for tenants of The Atrium Business Center, subject to the rules and
regulations established from time to time by Landlord. Said parking shall be at
no expense to the Tenant unless a tax, fee or levy is imposed directly or
indirectly by a Federal, State or local agency or jurisdiction for parking. If
such a tax, fee or levy is imposed tenant agrees to pay its portion of said fee
as reasonably determined by the Landlord.

24.  AUTHORITY OF PARTIES.

24.1 Corporate Authority. If Tenant is a corporation, each individual executing
this Lease on behalf of said corporation represents and warrants that he is duly
authorized to execute and deliver this Lease on behalf of said corporation, in
accordance with a duly adopted resolution of the Board of Directors of said
corporation or in accordance with the by- laws of said corporation, and that
this Lease is binding upon said corporation in accordance with its terms.

24.2 Limited Partnerships. Landlord herein is a limited partnership. It is
understood and agreed that any claims by Tenant on Landlord shall be limited to
the assets of the limited 


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partnership. And furthermore, Tenant expressly waives any and all rights to
proceed against the individual partners or the officers, directors or
shareholders of any corporate partner, except to the extent of their interest in
said limited partnership.

25.  GENERAL PROVISIONS.

25.1 Exhibits. Exhibits attached hereto, and addendums initialed by the parties,
are deemed to constitute a part hereof.

25.2 Waiver. The waiver by Landlord of any provision of this Lease shall not be
deemed to be a waiver of any subsequent breach of the same or any other
provisions of this Lease herein contained. The subsequent acceptance of rent
hereunder by Landlord shall not be deemed to be a waiver of any preceding breach
by Tenant of any provision of this Lease, other than the failure of the Tenant
to pay the particular rental so accepted, regardless of Landlord's knowledge of
such preceding breach at the time of the acceptance of such rent.

25.3 Notices. All notices and demands which may or are required to be given by
either party to the other hereunder shall be in writing. All notices and demands
by the Landlord to the Tenant shall be sufficient if delivered in person or sent
by first class mail, postage prepaid, addressed to the Tenant at the Premises or
to such other place as Tenant may from time to time designate in a written
notice to the Landlord. All written notices and demands by the Tenant to the
Landlord shall be sufficient if delivered in person or sent by first class mail,
postage prepaid, addressed to the Landlord at the office of the building or to
such other person or place as the Landlord may from time to time designate in a
notice to the Tenant. Any such notice is effective at the time of delivery or 48
hours after mailing.

25.4 Rentable Area. Rentable square footage, as herein used, is the actual
square footage of the office suite plus a load factor for gallerias, restrooms,
hallways and other common areas. The stated rentable area will not be used as a
basis for either party making any claim against the other.

25.5 Joint and Several Obligations. If there be more than one Tenant, the
obligations hereunder imposed upon tenants shall be joint and several.

25.6 Captions. The captions of the paragraphs of this Lease are 



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<PAGE>   16



not a part of this Lease and shall have no effect upon the construction or
interpretation of any part hereof.

25.7  Time.  Time is of the essence hereof.

25.8 Successors and Assigns. The provisions of this Lease, subject to the
provisions as to assignment, apply to and bind the successors and assigns of the
parties hereto.

25.9 Recording. Neither Landlord nor Tenant shall record this Lease or a short
form memorandum hereof without the prior written consent of the other party.

25.10 Scope and Amendments. This Lease is and shall be considered to be the only
agreement between the parties hereto. All negotiations and oral agreements
acceptable to both parties are included herein. No amendment or other
modification of this Lease shall be effective unless in a writing signed by
Landlord and by Tenant.

25.11 Legal Fees. In the event of any action brought by either party against the
other under this Lease, the prevailing party shall be entitled to recover all
costs including the fees of its attorneys as the court may adjudge reasonable.

25.12 Sale. In the event of any sale of the building, Landlord shall be released
of any liability under this Lease, and the purchaser of the Premises shall be
deemed to have assumed and agreed to carry out all of the obligations of the
Landlord under this Lease.

25.13 Lender Requirements. Upon request of the Landlord, Tenant will, in
writing, subordinate its rights hereunder to the rights of any mortgagee, under
a deed of trust held by any bank, insurance company or other lending
institution, (collectively Lender) now or hereafter in force against the land
and building of which the Premises are a part, and to all advances made or
hereafter to be made upon the security thereof. If any proceedings are brought
for foreclosure, or in the event of the exercise of the power of sale under any
mortgage or deed of trust made by the Landlord covering the Premises, the Tenant
shall recognize such purchaser as the Landlord under this Lease. Tenant's
obligation to subordinate it's rights hereunder is conditioned upon Lender's
agreement not to disturb Tenant's possession or quiet enjoyment of Premises.




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<PAGE>   17



25.14 Name. Tenant shall not use the name of the development in which the
Premises are situated for any purpose other than as an address of the business
to be conducted by the Tenant in the Premises, unless written authorization is
obtained from Landlord.

25.15 Severability. Any provision of this Lease which shall prove to be invalid,
void or illegal shall in no way affect, impair or invalidate any other provision
hereof.

25.16 Applicable Law. This Lease shall be governed by the laws of the State of
California.

25.17 Toxics. Landlord and Tenant acknowledge that they have been advised that
numerous federal, state, and/or local laws, ordinances and regulations ("law")
affect the existence and removal, storage, disposal, leakage of contamination by
materials designated as hazardous or toxic ("Toxics"). Many materials, some
utilized in everyday business activities and property maintenance, are
designated as hazardous or toxic. Some of the Laws require that Toxics be
removed or cleaned up without regard to whether the party required to pay for
the "clean up" caused the contamination, owned the property at the time the
contamination occurred or even knew about the contamination. Some items, such as
asbestos or PCB's, which were legal when installed, now are classified as
Toxics, and are subject to removal requirements. Civil lawsuits for damages
resulting from Toxics may be filed by third parties in certain circumstances.
Tenant and Landlord agree to hold the other harmless from any responsibility for
any Toxics which are brought on to the Premises or the project by themselves,
their agents, employees or contractors.

25.18 SIGNAGE. The original standard tenant identification sign on the main door
to the Premises will be installed at Landlord's expense. Landlord will not
charge Tenant for this sign for the duration of the lease unless Tenant requests
a change in the sign.

26.  ELECTRICAL, COMMUNICATIONS AND ALARM WIRING.

26.1 Tenant shall contact the Landlord prior to installing or relocating any
electrical, telephone, network, LAN, intercom, doorbell, or alarm wiring systems
at the Atrium Business Center.

26.2 All electrical wiring shall be installed by a licensed 



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contractor in expanded metal tubing in accordance with the most current
electrical code, etc.

26.3 All communication cabling shall be installed by a licensed contractor and
shall be plenum rated and shall not be installed as to "lay" on ceiling tile or
t-bar grid systems. A certificate of compliance shall be provided by contractor
to Landlord at time of completion.

26.4 Landlord shall not be financially responsible for any repair or replacement
of any communication cables, telephone lines, telephone feeders, or trunk lines
beyond the M.P.O. (minimum point of entry) established by Pacific Bell. If one
or more of these lines serve several tenants, the cost of installation and
repair shall be divided among tenants currently being served by said cable.

26.5 Not all existing telephone rooms/punchdown boards are permanent. Tenant and
his contractor must verify location of termination points with the Landlord
prior to installation.

26.6 No audible alarm systems will be permitted. Landlord will not assume any
financial responsibility for any alarms attributable to its employees,
contractors, including janitors, guards, or service personnel.

26.7 Any work requiring access to adjoining tenant spaces shall be prearranged
so that Landlord can obtain permission for the intrusion/interruption of the
space. Tenant shall reasonably cooperate in arranging access to contractors for
adjoining tenant when requested by Landlord.

26.8 Upon request of Landlord, Tenant shall remove all communication cable that
Tenant has installed in the Premises upon expiration of this Lease and repair
all damage caused by said removal.

27. ASSIGNMENT OF RENTS. In the event of Tenant's receipt of a Notice from
Principal Mutual Life Insurance Company or its nominee that Landlord is in
default under its mortgage, Tenant shall make all future rent payments directly
to Principal at the address Lender directs in the Notice.

28. AMERICANS WITH DISABILITIES ACT. Landlord believes the Premises complies
with the "Americans With Disabilities Act" 





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(ADA), but no independent investigation has been made to ensure compliance with
the "Americans With Disabilities Act" (ADA). This Act may require a variety of
changes to a facility, including potential removal of barriers to access by
disabled persons and provision of auxiliary aids and services for hearing,
vision or speech impaired persons, some of which would be the Landlord's
responsibility and some would be the Tenant's responsibility. Landlord urges all
parties to obtain independent legal and technical advice with respect to the
physical and environmental conditions and ADA compliance of the Property. The
Parties agree that it will rely solely on their own investigations and/or that
of a licensed professional specializing in these areas, and not on the
investigation, assurances or opinion of Landlord or Broker, if any.

29. BROKERS. Tenant warrants that it has had no dealing with any real estate
broker or agent in connection with the negotiation of this Lease excepting only
of Thrust IV, and it knows of no other real estate broker or agent who is
entitled to a commission in connection with this Lease. Commissions shall be
paid by Landlord to Broker(s) on the following schedule: 50/50 - 6%, 5%, 4%. No
commissions shall be paid on Tenant Improvement Amortizations, CPI Increases or
any other rent adjustment covered in section 4.2 herein. No commission shall be
paid by Tenant.

30. CARPETS. Landlord shall, at its cost, clean the carpets on or before August
31, 1998.

31. COVERED PARKING. The covered parking in the rear of the building will
continue, at the discretion of the Landlord, to be assigned in accordance with
the January 26, 1993 letter from Landlord to Tenant.

32. EXTRA HVAC AND UTILITY USAGE. Except for Tenant's computer room and machine
room, Landlord acknowledges that Tenant's current use of utilities in the
Premises is not in excess of that usually furnished for use of the Premises as
general office space. Landlord has (1) disconnected the supplemental
air-condition system serving the Machine Room on the 2nd floor, (2) installed an
outside air supply and exhaust system to said Machine Room, and (3) disconnected
the reheat and humidifier system in the main Computer Room on the 1st floor.
Landlord and Tenant shall share equally the "electrical cost" of operating the
above fans and the remaining two supplemental air-condition units supplying the
Computer Room. This cost is now estimated to be 





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$2,981.66 per month (Tenant's share = $1,490.83). When that energy demand (on a
yearly average) is changed on either or both of these rooms, or the electric
rate changes, the electric cost shall be changed to reflect such different usage
or rate. Landlord shall establish a preventive maintenance program and both
arrange for and pay for all maintenance and repair directly with a service
company, and Tenant shall reimburse the Landlord one-half the costs thereof.

33. Tenant shall also be directly responsible for arranging and paying for any
and all costs of maintaining and/or repairing of the HALON fire extinguishing
system in Tenant's computer room.

34. Tenant shall be directly responsible for the private access system and door
hardware related to Tenant's security system, which shall not include the two
exterior doors and the spa door which the Landlord has replaced with its own
system.

35. Main Building "House Air" system operates on a standard office building
schedule of 7AM to 6PM on weekdays. Any after hours/weekend cooling required by
Tenant will be billed to Tenant on an hourly rate of $24.00 for one side of the
building and $39.00 for both sides, with a six hour daily minimum. Said rate
shall be adjusted by Landlord from time to time to reflect rate and usage
changes. To request this extra service Tenant will phone Landlord and then FAX
the main office with Tenant's exact requirements no later than 12 noon on a
weekday preceding the after hours or weekend of desired usage.

36. Landlord agrees that Tenant is not responsible for the security of other
Tenants in the building and that Tenant's retention of dedicated guard service,
and dedicated security system or dedicated perimeter alarm system does not make
Tenant responsible for the security of other Tenants.

37. Tenant's private phone system and Tenant's private security access system
shall remain the sole responsibility of the Tenant and Landlord shall have no
responsibility for said private phone and security systems.

38. Amendments To The Above.

Delete Paragraphs 6.1 & 6.2

Paragraph 7.2c; delete the last sentence and add in its place, "In 





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matters related to Tenant's improvements or activity, Tenant shall at its cost
promptly comply with all laws now in force or which may hereafter be in force
and with the requirements of any board of fire underwriters or other similar
body."

Paragraph 8, Page 5, Line 2; after, "shall belong to the",delete, "Landlord and"
and add "Tenant during the term of this Lease but"...

Paragraph 8, Page 5, Line 3; after, "surrendered with the Premises", add "and
shall become the property of the Landlord"...

Paragraph 8, Page 5, Line 8; after "alterations, additions or improvements",
delete "requested by Tenant" and add "done for or by the tenant unless the
Landlord has previously waived its right to ask for said removal".

Paragraph 8, Page 5; Insert the following at the end of the paragraph, "Tenant
may be permitted to make alternations and additions to the PRemises provided
that (1) Tenant first seeks Landlord's consent (which consent shall not be
unreasonably withheld), and (2) such alterations and additions are constructed
by or under the direction of Landlord as general contractor, Landlord agrees to
make such alterations and/or additions at competitive prices and that its
charges for supervision and/or overhead will not exceed 15% and (3) a deposit to
cover the cost of removal of the improvements and restoring of the premises may
be required by the Landlord"

Paragraph 10, Page 6, Line 1; after "Tenant shall pay to Landlord", add "or
Insurance Company."

Paragraph 10, Page 6, Line 2; after "maintenance and repairs", add "subject
however to the provisions of Paragraph 13.3."

Paragraph 11, Page 6; Insert at the end of the first sentence, "which will not
be unreasonably withheld".

Paragraph 11, Page 6, Insert the following at the end of Paragraph 11 as amended
above: "The provisions of this paragraph shall not apply to any transfer or
assignment of the Lease to any entity resulting from a merger of ,
reorganization of or consolidation with Tenant; or to any entity which acquires
all or substantially all of the assets of Tenant, as a going concern, with
respect to the business that is being conducted in the Premises provided that 



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<PAGE>   22


if such entity does not have the same financial strength as Tenant, in
Landlord's sole judgement, Landlord shall have the right to demand reasonable
additional security for the Lease."

Paragraph 12, Page 7, Line 2, after "negligence or willful misconduct of
Landlord", insert "or a willful breach of the lease by the Landlord,"

Paragraph 16, Page 9, Line 3; after "this Lease, as well as such", insert
"nondiscriminatory"

Paragraph 16, Page 9, Line 4; after "shall from time to time", insert
"reasonable"

Paragraph 18, Page 10, Line 8. Insert the following at the end of the first
sentence: "In exercising its rights pursuant to the prior sentence. Landlord
agrees to use its best efforts to minimize any disruption to tenant occasioned
by such entry".

Paragraph 19, Page 11, Insert at the end of the last sentence, "nor shall the
following termination clause apply."

Paragraph 19, Page 11 Insert at the end of the paragraph, "If one-third or more
of the Premises is rendered unusable the following shall apply:
        (a) Landlord shall give notice to Tenant of its election to rebuild or
not to rebuild the Premises within Forty Five (45) days of casualty to the
Premises and such notice shall specify Landlord's architect's or engineer's
reasonable estimate as to the time required to rebuild or restore the Premises;
        (b) If, in the reasonable opinion of Landlord's architect or engineer,
the Premises will take longer than nine (9) months to rebuild or restore and
Landlord has elected to perform such rebuilding or restoration, Tenant may,
notwithstanding Landlord's election, terminate this Lease by written notice to
Landlord of such termination within five (5) days after its receipt of
Landlord's notice. Such termination shall be effective as of the date of the
casualty as to the unusable space and 180 days after Landlords receipt of
Tenant's termination notice as to the remainder of the premises.
        (c) If the remaining unusable space is more than one-third of the
Premises and Landlord fails to restore this unusable portion of the Premises
(including reasonable means of access thereto) within a period which is sixty
days longer than the period stated in Landlord's notice to Tenant as the
estimated rebuilding period, 






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<PAGE>   23



Tenant may by giving notice to Landlord prior to the expiration of the 60 days
immediately terminate this Lease as to the remaining unusable space, in which
event the Lease on the remaining usable space shall terminate 180 days after the
date of the giving of such notice.

Paragraph 20.1d, Page 11; Change "sixty (60) days" to "ninety (90) days" and
change the first "thirty (30) days" to "sixty (60) days" and change the second
"thirty (30) days" to "ninety (90) days"

Paragraph 26.5, Page 17; add at the end of the paragraph, "of new phone and data
lines."

Paragraph 26.8, Page 18; add at the end of the paragraph, "Notwithstanding the
above, if the communication lines were installed with Landlord's permission, in
a manor previously approved by Landlord and they meet current code and they are
in good working order and they are useful to the next tenant, Landlord shall not
request the lines meeting all of the above criteria to be removed."

This lease supersedes all previous Leases, Modifications, Written Agreements and
Oral Agreements.

The parties hereto have executed this Lease on the dates specified immediately
adjacent to their respective signatures.


LANDLORD:    EL CAMINO OFFICE INVESTMENTS
              By:  THRUST IV, INC., General Partner


By:      Hugh P. Bikle                     Date:     March 18, 1998
        -------------------------
        Hugh P. Bikle, President


TENANT:  INTELLICORP, INC.


By:      K. Czaja                          Date:     March 18, 1998
        -------------------------         
         (SIGNATURE)

         K. A. Czaja       CFO             Tax ID#  94-275-6073
        -------------------------
         (PRINT NAME)  (TITLE)





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LENDER:  PRINCIPAL FINANCIAL GROUP


By:___________________________              Date:_________________
         (SIGNATURE)


   ---------------------------
     (PRINT NAME) (TITLE)

Attachments:

Exhibit A - Floor Plan with Suite marked
Exhibit B - Rules & Regulations


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                                   EXHIBIT "A"


                          Floor Plan with Suite marked






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                                   EXHIBIT "B"


                               Rules & Regulations






                                       26