Patent Publication Number: US-11393288-B2

Title: Method of gaming, a gaming system and a game controller

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/113,754, filed Aug. 27, 2018 which is a continuation of U.S. patent application Ser. No. 15/141,420, filed Apr. 28, 2016, which claims the benefit of priority to Australian Provisional Patent Application No. 2015901517, filed Apr. 29, 2015, the entire contents and disclosure of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     The present invention relates to a method of gaming, a gaming system and a game controller. 
     Gaming systems are known that have a re-spin feature where a player can select an option to hold one or more spinning reels. The one or more held reels may be used in the generation of a subsequent game outcome. 
     While such gaming systems provide players with enjoyment, a need exists for alternative gaming systems in order to maintain or increase player enjoyment. 
     BRIEF DESCRIPTION 
     In one aspect, an electronic method of gaming is provided. The method is implemented using gaming system. The gaming system includes a display configured to display a wagering game, a player input interface, a credit input mechanism, and a game controller. The credit input mechanism includes at least one of a card reader, a ticket reader, a bill acceptor, and a coin input mechanism, and is configured to establish a credit balance that is increasable and decreasable based on wagering activity. The method includes receiving, via the credit input mechanism, a credit wager to initiate play of a base game. The method also includes awarding, by the game controller, in a feature game, at least two game rounds. The at least two game rounds include at least an initial game round and a subsequent game round. The method further includes generating, be the game controller, a plurality of candidate game outcomes for a plurality of game rounds. The method also includes determining, by the game controller, for each of the plurality of candidate game outcomes, an expected player benefit to be gained from the respective candidate game outcome when generating a subsequent game outcome in the subsequent game round. The method still further includes selecting, by the game controller, a candidate game round from the plurality of candidate game rounds having a candidate game outcome of the plurality of candidate game outcomes associated with a greatest expected benefit, and displaying the selected candidate game round on the display of the gaming system as the initial game round. 
     In another aspect, a gaming system is provided. The gaming system includes a display configured to display a wagering game, a player input interface, a credit input mechanism, and a game controller. The credit input mechanism includes at least one of a card reader, a ticket reader, a bill acceptor, and a coin input mechanism. The credit input mechanism is configured to receive a credit wager to initiate play of a base game, and establish a credit balance that is increasable and decreasable based on wagering activity. The game controller is configured to award, in a feature game, at least two game rounds. The at least two game rounds include at least an initial game round and a subsequent game round. The game controller is also configured to generate a plurality of candidate game outcomes for a plurality of game rounds. The game controller is further configured to determine, for each of the plurality of candidate game outcomes, an expected player benefit to be gained from the respective candidate game outcome when generating a subsequent game outcome in the subsequent game round. The game controller is still further configured to select a candidate game round from the plurality of candidate game rounds having a candidate game outcome of the plurality of candidate game outcomes associated with a greatest expected benefit, and display the selected candidate game round on the display as the initial game round. 
     In yet another aspect, a game controller for a gaming system is provided. The gaming system includes a display configured to display a wagering game, a player input interface, and a credit input mechanism. The credit input mechanism includes at least one of a card reader, a ticket reader, a bill acceptor, and a coin input mechanism, and is configured to establish a credit balance that is increasable and decreasable based on wagering activity. The game controller includes a processor configured to receive an indication of a credit wager input to the credit input mechanism to initiate play of a base game. The game controller also includes a game awarder configured to award, in a feature game, at least two game rounds. The at least two game rounds include at least an initial game round and a subsequent game round. The game controller further includes a game outcome generator configured to generate a plurality of candidate game outcomes for a plurality of game rounds. The game controller also includes a candidate game outcome assessor configured to determine, for each of the plurality of candidate game outcomes, an expected player benefit to be gained from the respective candidate game outcome when generating a subsequent game outcome in the subsequent game round. The candidate game outcome assessor is also configured to select the candidate game round from the plurality of candidate game rounds having a candidate game outcome of the plurality of candidate game outcomes associated with a greatest expected benefit. The game controller still further includes a display controller configured to control the display of the gaming system to display the selected candidate game round as the initial game round. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention will now be described with reference to the accompanying drawings in which: 
         FIG. 1  is a block diagram of exemplary core components of a gaming system; 
         FIG. 2  is a perspective view of an exemplary standalone gaming machine; 
         FIG. 3  is a block diagram of exemplary functional components of a gaming machine; 
         FIG. 4  is a schematic diagram of exemplary functional components of a memory; 
         FIG. 5  is a schematic diagram of an exemplary network gaming system; 
         FIG. 6  is a further block diagram of an exemplary gaming system; 
         FIG. 7  is a flow chart of an exemplary method of electronic gaming; 
         FIG. 8  is an exemplary screen shot that may be used with the gaming machine of  FIGS. 2 and 3  and/or with the gaming system of  FIGS. 1, 5 , and  6 ; and 
         FIG. 9  is an exemplary screen shot that may be used with the gaming machine of  FIGS. 2 and 3  and/or with the gaming system of  FIGS. 1, 5 , and  6 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, there is shown a gaming system including a game controller. The gaming controller includes components that enable the implementation of a game, wherein when at least two game rounds (i.e., an initial game round and at least one subsequent game round) are awarded, a plurality of candidate game rounds are generated, one of which is selected as the initial game round. The gaming system assesses a game outcome of each of the candidate game rounds. In one embodiment, the candidate game round associated with the candidate game outcome that is assessed by the gaming system as being able to provide the greatest benefit in a subsequent game round is provided to the player as the initial game round. The player is then provided with an opportunity by the gaming system to select part of the game to be kept or held for a subsequent spin. For example, in one aspect, the player may select one or more reels to be “held” for a subsequent re-spin. 
     General Construction of an Exemplary Gaming System 
     The gaming system can take a number of different forms. In a first aspect, a standalone gaming machine is provided wherein all or most components required for implementing the game are present in a player operable gaming machine. 
     In a second form, a distributed architecture is provided wherein at least some of the components required for implementing the game are present in a player operable gaming machine and at least some of the components required for implementing the game are located remotely from the gaming machine. For example, a “thick client” architecture may be used wherein part of the game is executed on a player operable gaming machine and part of the game is executed remotely, such as by a gaming server. Alternatively, a “thin client” architecture may be used wherein most of the game is executed remotely from the gaming machine, such as by a gaming server and a player operable gaming machine is used only to display audible and/or visible gaming information to the player and receive gaming inputs from the player. 
     However, it will be understood that other arrangements are envisaged. For example, an architecture may be provided wherein a gaming machine is networked to a gaming server and the respective functions of the gaming machine and the gaming server are selectively modifiable. For example, the gaming system may selectively operate in standalone gaming machine mode, “thick client” mode or “thin client” mode depending on several factors, including, for example, the game being played, operating conditions, and/or other factors. Other variations will be apparent to persons skilled in the art. 
       FIG. 1  is a block diagram of exemplary core components  80  of a gaming system  75 . Irrespective of the form, gaming system  75  includes several core components  80 . At the broadest level, exemplary core components  80  are a player interface  50  and a game controller  60 . Player interface  50  is arranged to enable manual interaction between a player and gaming system  75  and, as such, includes input/output components  52 ,  54 ,  56 ,  58  required for the player to enter instructions to play the game and observe the game outcomes. 
     Components of player interface  50  may vary from embodiment to embodiment but will typically include at least a credit mechanism  52  to enable a player to input credits and to receive payouts, at least one display  54 , a game play mechanism  56  including one or more input devices that enable a player to input game play instructions (e.g. to place a wager), and one or more speakers  58 . 
     Game controller  60  is in data communication with player interface  50  and typically includes a processor  62  that processes the game play instructions in accordance with game play rules and outputs game play outcomes to display  54 . Typically, the game play rules are stored as program code in a memory  64  but can also be hardwired. As used herein, the term “processor” refers generically to any device that can process game play instructions in accordance with game play rules and may include, for example, a microprocessor, microcontroller, programmable logic device or other computational device, a general purpose computer (e.g. a PC) or a server. That is, a processor  62  may be provided by any suitable logic circuitry for receiving inputs, processing them in accordance with instructions stored in memory  64  and generating outputs (for example on display  54 ). Such processors are sometimes also referred to as central processing units (CPUs). Most processors are general purpose units, however, it is also know to provide a specific purpose processor using an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). 
       FIG. 2  illustrates a gaming system  75  in the form of an exemplary standalone gaming machine  10 . In the exemplary embodiment, gaming machine  10  includes a console  12  having a display  14  on which are displayed representations of a game  16  that can be played by a player. A mid-trim  20  of gaming machine  10  houses a bank of buttons  22  for enabling a player to interact with gaming machine  10 , in particular during game play. Mid-trim  20  also houses a credit input mechanism  24 . In the exemplary embodiment, credit input mechanism  24  includes a coin input chute  24 A and a bill collector  24 B. Other credit input mechanisms may also be employed, such as, for example, a card reader for reading a smart card, debit card, and/or credit card. Other gaming machines may be configured for ticket use, in that these gaming machines include a ticket reader for reading tickets having a value and for crediting the player based on the face value of the ticket. A player marketing module (not shown) having a reading device may also be provided for the purpose of reading a player tracking device, for example, as part of a loyalty program. The player tracking device may be in the form of a card, flash drive, or any other portable storage medium capable of being read by the reading device. In some embodiments, the player marketing module may provide an additional credit mechanism, either by transferring credits to the gaming machine from credits stored on the player tracking device or by transferring credits from a player account in data communication with the player marketing module. 
     A top box  26  may carry artwork  28 , including, for example, pay tables and details of bonus awards and other information or images relating to the game. Further artwork and/or information may be provided on a front panel  29  of console  12 . In the exemplary embodiment, a payout mechanism such as a coin tray  30  is mounted beneath front panel  29  for dispensing cash payouts from gaming machine  10 . 
     In the exemplary embodiment, display  14  is a video display unit, particularly a cathode ray tube screen device. Alternatively, display  14  may be a liquid crystal display, plasma screen, any other suitable video display unit, or the visible portion of an electromechanical device. Top box  26  may also include a display, such as, for example, a video display unit, which may be of the same type as display  14 , or of a different type. 
       FIG. 3  illustrates a block diagram of exemplary functional components of a typical gaming machine  100 , which may be the same as or different to gaming machine  10  (shown in  FIG. 2 ). 
     Gaming machine  100  includes a game controller  101  including a processor  102  mounted on a circuit board. Instructions and data to control operation of processor  102  are stored in a memory  103  that is in data communication with processor  102 . Typically, gaming machine  100  will include both volatile and non-volatile memory and more than one of each type of memory, with such memories being collectively represented by memory  103 . 
     Gaming machine  100  includes hardware meters  104  for purposes including ensuring regulatory compliance and monitoring player credit, an input/output (I/O) interface  105  for communicating with peripheral devices of gaming machine  100 . I/O interface  105  and/or the peripheral devices may be intelligent devices with their own memory for storing associated instructions and data for use with the input/output interface or the peripheral devices. A random number generator module  113  generates random numbers for use by processor  102 . Persons skilled in the art will appreciate that the reference to random numbers includes pseudo-random numbers. 
     In the exemplary embodiment, a player interface  120  includes peripheral devices that communicate with game controller  101  including one or more displays  106 , a touch screen and/or input buttons  107  (which provide a game play mechanism), and a credit input mechanism such as a card and/or ticket reader  108 , a bill acceptor  110 , and/or coin input mechanism  110 . The credit input mechanism is configured to receive a credit wager to initiate play of a base game, and establish a credit balance (e.g., using the received credit wager) that is increasable and decreasable based on wagering activity within a game. Player interface  120  also includes a payout mechanism such as a printer  109  and/or a coin output mechanism  111 . The payout mechanism is configured to output a payout to a player of gaming machine  100  based on an outcome of the game (e.g., a base game and/or a feature game). Additional hardware may be included as part of gaming machine  100 , or hardware may be omitted as required for the specific implementation. For example, although buttons or touch screens are typically used in gaming machines to allow a player to place a wager and to initiate a play of a game, any input device that enables the player to input game play instructions may be used. For example, in some gaming machines, a mechanical handle may be used to initiate a play of the game. Persons skilled in the art will also appreciate that a touch screen can be used to emulate other input devices, such as, for example, a touch screen can display virtual buttons that a player can “press” by touching the screen where they are displayed. 
     In addition, gaming machine  100  may include a communications interface, for example, a network card  112 . Network card  112  may, for example, send status information, accounting information, or other information to a bonus controller, central controller, server, or database and receive data or commands from the bonus controller, central controller, server, or database. In embodiments employing a player marketing module, communications over a network may be via player marketing module—i.e., the player marketing module may be in data communication with one or more of the above devices and communicate with it on behalf of gaming machine  100 . 
       FIG. 4  is a block diagram of the main components  103 A,  103 B,  103 C of a memory  103 . In the exemplary embodiment, memory  103  includes RAM  103 A, EPROM  103 B, and a mass storage device  103 C. RAM  103 A typically temporarily holds program files for execution by processor  102  and related data. EPROM  103 B may be a boot ROM device and/or may contain some system- or game-related code. Mass storage device  103 C is typically used to store game programs, the integrity of which may be verified and/or authenticated by processor  102  using protected code from EPROM  103 B or elsewhere. 
     It is also possible for the operative components of gaming machine  100  to be distributed. For example, in one embodiment, input/output devices  106 , 107 , 108 , 109 , 110 , 111  are provided remotely from game controller  101 . 
       FIG. 5  illustrates an exemplary gaming system  200  in accordance with an alternative embodiment. Gaming system  200  includes a network  201 , which, for example, may be an Ethernet network. In the exemplary embodiment, gaming machines  202 , shown arranged in three banks  203  of two gaming machines  202 , are coupled to network  201 . Gaming machines  202  provide a player-operable interface and may be the same as gaming machines  10  and/or  100  (shown respectively in  FIGS. 2 and 3 ), or may have simplified functionality depending on the requirements for implementing game play. Although banks  203  of two gaming machines  202  are shown in the exemplary embodiment, banks of one, three, or more gaming machines  202  are also envisioned. 
     One or more displays  204  may also be coupled to network  201 . For example, displays  204  may be associated with one or more banks  203  of gaming machines  202 . Displays  204  may be used to display representations associated with game play on gaming machines  202 , and/or used to display other representations, for example, promotional or informational material. 
     In a thick client embodiment, a game server  205  implements part of the game played by a player using a gaming machine  202 , and gaming machine  202  implements part of the game. With this embodiment, as both game server  205  and gaming machine  202  implement part of the game, they collectively provide a game controller. A database management server  206  may manage storage of game programs and associated data for downloading or access by gaming machines  202  in a database  206 A. Typically, if gaming system  200  enables players to participate in a Jackpot game, a Jackpot server  207  will be provided to perform accounting functions for the Jackpot game. A loyalty program server  212  may also be provided. 
     In a thin client embodiment, game server  205  implements most or all of the game played by a player using a gaming machine  202 , and gaming machine  202  essentially provides only the player interface. In such an embodiment, game server  205  provides the game controller, and gaming machine  202  receives player instructions and transmits these instructions to game server  205 . Game server  205  processes the player instructions and returns game play outcomes to gaming machine  202  for display. In a thin client embodiment, such gaming machines  202  could be computer terminals, e.g., PCs running software that provides a player interface operable using standard computer input and output components. Other client/server configurations are possible, and further details of a client/server architecture can be found in WO 2006/052213 and PCT/SE2006/000559, the disclosures of which are incorporated herein by reference. 
     Servers are also typically provided to assist in the administration of gaming system  200 , including, for example, a gaming floor management server  208  and a licensing server  209  to monitor the use of licenses relating to particular games. An administrator terminal  210  is provided to allow an administrator to run network  201  and the devices connected to network  201 . 
     Gaming system  200  may communicate with other gaming systems, other local networks (for example, a corporate network), and/or a wide area network such as the Internet, for example, through a firewall  211 . 
     Persons skilled in the art will appreciate that in accordance with known techniques, functionality at the server side of network  201  may be distributed over a plurality of different computers. For example, elements may be run as a single “engine” on one server or a separate server may be provided. For example, game server  205  could run a random generator engine. Alternatively, a separate random number generator server could be provided. Further, persons skilled in the art will appreciate that a plurality of game servers could be provided to run different games or a single game server may run a plurality of different games as required by the terminals. 
     Further Details of the Exemplary Gaming System 
     In one embodiment, a gaming system is configured to provide a spinning reel game of chance in which a feature game can be triggered. When the feature game is triggered, a plurality of free games are awarded. Each free game includes an initial game round and at least one subsequent game round. Candidate game outcomes are generated for at least the initial game round, as described in more detail below. 
     In order to initiate a play of the gaming system, the player operates game play mechanism  56  to specify a wager that affects the win entitlement that will be evaluated for this play of the game, and the player initiates a play of the game. Hence, a player&#39;s win entitlement can vary from game to game, depending on player selections. In most spinning reel games, it is typical for the player&#39;s entitlement to be affected by the amount they wager and by selections they make (i.e., the nature of the wager). For example, a player&#39;s win entitlement may be based on how many lines they play in each game—e.g., a minimum of one line up to a maximum number of lines permitted by the game (noting that not all permutations of win lines may be available for selection)—and how much they wager per line. Such win lines are typically defined by a combination of symbol display positions, one from each reel. The symbol display positions are located relative to one another such that they form a line that extends across the reels. 
     In many games, the player&#39;s win entitlement is not strictly limited to the lines they have selected. For example, “scatter” pays may be awarded independently of a player&#39;s selection of pay lines, and may be an inherent part of the win entitlement. 
     In other embodiments, the player may obtain a win entitlement by selecting a number of reels to play and an amount to wager per reel. Such games may be marketed under the trade name “Reel Power” by Aristocrat Leisure Industries Pty Ltd. The selection of a reel means that each displayed symbol of the reel can be substituted for another symbol at one or more designated display positions. In other words, all symbols displayed at symbol display positions corresponding to a selected reel can be used to form symbol combinations with other symbols displayed at designated symbol display positions on the other reels. For example, if there are five reels and three symbol display positions for each reel, such that the symbol display positions comprise three rows of five symbol display positions, the symbols displayed in the center row may be used for non-selected reels. As a result, the total number of ways to win is determined by multiplying the number of active display positions of each reel (the active display positions being all display positions of each selected reel) and the designated display position of the non-selected reels. As a result, for five reels and fifteen display positions, there are 243 possible ways to win. 
       FIG. 6  illustrates another block diagram of an exemplary gaming system. In the exemplary embodiment, processor  62  of game controller  60  is shown implementing a number of modules based on program code and data stored in memory  64 . In other embodiments, the modules could be implemented in some other way, for example, by a dedicated circuit. 
     These modules implement functionality that enables the game controller to implement the game. An outcome generator  622  operates in response to the player&#39;s operation of game play mechanism  56  to place a wager and to initiate a play of the game. Outcome generator  622  generates a game outcome that is evaluated by an outcome evaluator  624 . In an embodiment, a symbol selector  622 A of outcome generator  622  selects symbols from base reels  641 A of symbol data  641 , using a random number generator  621 . The selected symbols are transmitted to a display controller  625 , which causes the selected symbols to be displayed on display  54  at a corresponding set of display positions. 
     In one embodiment, symbol selector  622 A selects symbols for display from a plurality of symbol sets corresponding to respective reels of a plurality of spinning reels. Base reels  641 A specify a sequence of symbols for each reel, such that symbol selector  622 A may select symbols by randomly selecting a stopping position in the sequence. In one example, three symbols of each of five reels may be displayed such that the symbols are displayed at fifteen corresponding display positions on display  54 . In another embodiment, a probability table stored in memory  64  is used to vary the odds of a particular stop position in the sequence being selected. Other techniques may be used to control the odds of particular outcomes occurring to thereby control the return to player of the game. 
     Outcome evaluator  624  compares and evaluates the selected symbols against a pay table  644  based on the wager placed by the player in order to determine whether to make one or more awards. Any awards are made by a prize awarder  624 A by increasing or updating meters  645  and are also displayed on display  54  via display controller  625 . Outcome evaluator  624  also includes a trigger monitor  624 B that monitors the symbols selected by symbol selector  622 A to determine whether a trigger condition is satisfied. In one example, to satisfy the trigger condition, a defined number of scatter symbols must be selected by symbol selector  622 A. If the trigger condition is not satisfied, the play of the game ends (assuming the player does not exercise a gamble option, such as a “double-or-nothing” gamble option). 
     If the trigger condition is satisfied, a feature game is triggered. The feature game includes a number of free games that are awarded by outcome evaluator  624  and carried out by gaming system  75 . In one embodiment, the number of free games depends on the number of scatter symbols that are selected by symbol selector  622 A. In one embodiment, each free game includes at least two game rounds. 
     In an initial game round, an initial game outcome is selected by game outcome generator  622 , as described further herein. The initial game outcome is displayed on display  54  under the control of display controller  625 . The player is then presented with an option to “keep” or “hold” none, part, or all of the initial game outcome. Holding part of the initial game outcome includes, for example, holding one or more reels that will not be re-spun in a subsequent game round. The player&#39;s selections and instructions to hold any part(s) of the initial game outcome are processed by and stored in a reel holder  622 B, and may be further stored in memory  64 . Any part(s) of the initial game outcome that are not held by the player are reselected by game outcome generator  622 . 
     In one embodiment, for each initial game round of each free game, symbol selector  622 A generates a plurality of candidate game outcomes. Each candidate game outcome is selected by symbol selector  622 A from feature reels  641 B. These candidate game outcomes are stored in memory  64  as candidate data  642 . A candidate outcome assessor  623  assesses each candidate outcome based on assessment data  643 , which enables the candidate outcome assessor  623  to assess which candidate game outcome would provide the greatest benefit when generating a subsequent game round in the free game. In one embodiment, as described in further detail below, assessment data  643  includes criteria for assessing each candidate game outcome to determine the “greatest benefit.” The criteria specifies that the candidate game outcome that provides the “greatest benefit” is the candidate game outcome with the highest optimal expected win amount. In another embodiment, the criteria may identify a “greatest benefit” to the player in terms of interest to the player. For example, in such an embodiment, candidate outcome assessor  623  may assess the candidate game outcomes to determine which candidate game outcome would provide the most wins or the highest individual win amount. 
     In one embodiment, candidate outcome assessor  623  calculates the result of every combination of holding reels for each candidate game outcome, identifies the hold combination for each respective candidate game outcome that results in the highest average return to the player, and compares the highest average return across all candidate game outcomes to find the overall “best” candidate game outcome (e.g., the candidate game outcome associated with the overall highest average return). 
     For example, in one embodiment, three candidate game outcomes are assumed to be generated. For each candidate game outcome, if there are 5 reels, there are 32 different hold patterns, or ways to hold the reels (5 reels, either held or unheld; 2{circumflex over ( )}5=32). For each of the 32 different hold patterns, the candidate outcome assessor  623  determines the expected win amount from that particular hold pattern. 
     The “optimal hold pattern” will be the hold pattern with the highest expected win amount. Candidate outcome assessor  623  then compares the expected win amounts of the respective optimal hold pattern of each candidate game outcome. Candidate outcome assessor  623  selects the candidate game outcome that is expected to deliver the greatest benefit (e.g., the candidate game outcome with an optimal hold pattern with the overall highest expected win amount) and causes display controller  625  to display the selected candidate game outcome. 
     The selected symbols of the plurality of reels are displayed by display controller  625  on display  54  together with a message instructing to the player to touch reels to select which reels the player wishes to be held. In one embodiment, an indicator provided on the display enables the player to determine whether they have made an “optimal” selection. In one embodiment, the player can choose not to hold any reels or can choose to hold all reels. In one embodiment, gaming system  75  prevents the player from making invalid selections, such as a selection that would automatically result in a loss. To make a selection of reels to hold, the player uses game play mechanism  56 , for example, by touching one of the reels on a touchscreen of game play mechanism  56 . The selected reels are held by reel holder  622 B of game outcome generator  622 . Symbol selector  622 A then selects symbols for the remaining, un-held reels from feature reels  641 B in the same manner described above. These selected symbols are then displayed on display  54  in conjunction with the held symbols of the held reels. All of the displayed symbols are evaluated by outcome evaluator  624 . 
     In some embodiments, the player may then be provided with a further option to hold the same reels that the player already selected to hold. In one example, where gaming system  75  determines that the player makes “sub-optimal” decisions with respect to selecting which reels to hold, the player is provided with an increased chance of being awarded one or more additional re-spin rounds. For example, a calculation is performed by a player selection monitor  626  using an optimal hold determiner  626 A that determines whether the player has made the optimal hold by selecting an optimal hold pattern. 
     In such an embodiment, after determining that the player has made a sub-optimal selection, player selection monitor  626  determines whether to award one or more re-spin game rounds in order to preserve an appropriate return to player. For example, the chances of player selection monitor  626  awarding a re-spin round may be derived from a calculation as to the return to player “lost” by the player&#39;s sub-optimal selection. After determining to award an additional re-spin round, player selection monitor  626  causes a message to be output to the player to make an additional selection of reels, and game outcome generator  622  generates an additional re-spin round, after the player made their selection of which reels to hold. 
     For each re-spin, a corresponding subsequent game outcome is evaluated by outcome evaluator  624  based on pay table  644 . Prize awarder  624 A determines whether to award any prize by adding a win to meters  645 . In such an embodiment, the game then proceeds to the next free game. Each free game involves an additional cycle of game rounds, including an initial game round, in which candidate game outcomes are generated by the game outcome generator  622  and are assessed by candidate outcome assessor  623 , and then a subsequent, “re-spin” game round in which one or more reels are re-spun based on the selection by the player. 
       FIG. 7  is a flow chart of an exemplary method  700  of electronic gaming. In the exemplary embodiment, method  700  includes conducting  705  a base game, and determining  710  whether a trigger is satisfied. After a trigger is not satisfied, then an additional base game will be conducted assuming the player places an additional wager. Method  700  includes generating  715  candidate game outcomes, assessing  720  the game outcomes, selecting  725  and displaying a game outcome, and receiving  730  a hold selection from a player. Method  700  then involves determining  745  whether the hold is optimal and if it is not optimal, the player selection monitor  626  determines  710  whether to compensate  750  a player for the sub-optimal selection by an awarding the player an additional re-spin. The subsequent game outcome is generated  755  based on the hold selection and is evaluated  760  to determine whether to award any prizes based on pay table. The process then reverts to generating  715  candidate game outcomes until each of the free games are exhausted. 
     Further aspects of the method will be apparent from the above description of the system. It will be appreciated that at least part of the method will be implemented electronically, for example, digitally by a processor executing program code such as in the above description of a game controller. In this respect, in the above description certain steps are described as being carried out by a processor of a gaming system, it will be appreciated that such steps will often require a number of sub-steps to be carried out for the steps to be implemented electronically, for example due to hardware or programming limitations. For example, to carry out a step such as evaluating, determining or selecting, a processor may need to compute several values and compare those values. 
     As indicated above, the method may be embodied in program code. The program code could be supplied in a number of ways, for example on a tangible computer readable storage medium, such as a disc or a memory device, e.g. an EEPROM, (for example, that could replace part of memory  103 ) or as a data signal (for example, by transmitting it from a server). Further different parts of the program code can be executed by different devices, for example in a client server relationship. Persons skilled in the art, will appreciate that program code provides a series of instructions executable by the processor. 
     In some embodiments, an eligibility criteria may be applied for the player to be eligible for the re-spin feature game, for example, that the player has made a wager of a certain size, made an ante bet, selected all win lines, or played sufficient games, or the player is a member of a loyalty program. 
     As indicated above, the trigger condition may be satisfied by an occurrence of a symbol combination in the game; however, other trigger conditions could be used, for example, occurrence of a specific symbol in the game, purchase of a trigger, or a trigger may be caused by another connected system, based on turnover, based on a random evaluation, etc. 
     Typically, a win will result in some form of award being made, such as an award of credits. Such an award may never actually be physically received by a player. For example, many gaming systems provide a player with a “double or nothing” gamble feature, where the player can double or forfeit their credits before commencing another play of the game or cashing out. Further, as credits are fungible, once credits have been added to the credit meter, it is not possible to distinguish between credits that the player has input as cash or the like and credits resulting from an award. 
     EXAMPLE 
       FIGS. 8 and 9  show exemplary screen shots from an exemplary game, “Red Queen”, implemented by a gaming system in accordance with one embodiment. Red Queen is a 4×5 Reel Power game with a hold and re-spin free games feature. Each free game feature consists of an initial spin and one or more subsequent re-spins in which the player may selectively hold reels. 
     During the game, a “WILD” symbol substitutes for all symbols except scatters. 
     All wins are evaluated from left to right only, except scatters, which pay in any position provided the positions are in “bought” positions. All wins are multiplied by the bet multiplier, including scatter wins. 
     Moreover, in the game, 7, 10, or 25 free games are won with any 3, 4, or 5 SCATTER symbol win, respectively. That is, 3 or more SCATTER symbols trigger the feature and award different numbers of free games. 
     Each free game consists of an initial spin game round and at least one subsequent re-spin game round. For the initial spin round, all 5 reels are spun. For each re-spin round, the player may optionally hold one or more reels. 
     In one embodiment, non-optimal hold selections in re-spin rounds are compensated by an increased chance of additional re-spin game rounds being awarded to the player. All hold selections are guaranteed a minimum expected return to player. Game outcomes are evaluated, and wins are paid after each re-spin round. Wins are not paid for the initial spin round. 
     Feature reels are used during the free games. All scattered SCATTER symbols are removed from all reels during the free games. All reels (Reels 1-5) are played during the feature irrespective of the wager. The bet multiplier for the feature is the same as the bet multiplier for the base game that triggered the feature. 
     Each initial spin round is selected from a set of candidate spin rounds. A number of candidate spin game rounds are generated in the background. For each candidate spin round, the expected win from an “optimally held re-spin” is calculated. The candidate spin round with the highest expected re-spin win is selected as the initial spin round. The number of candidate spin rounds is determined from a weighting table. 
     For each re-spin round, the player may hold or unhold a reel by touching the reel on screen. 
     The player may hold none or all of the reels. On a second or subsequent re-spin round, the player may toggle previously held or unheld reels. After making hold selections, the player presses PLAY to re-spin any unheld reels. The number of re-spin rounds for each free game is determined in such a way that the expected win from the entire free game (i.e., the total from all re-spin rounds) is bounded within a range. 
     The gaming system is configured so that the player cannot hold a combination of reels if the expected win from the subsequent re-spin is zero. If the player presses PLAY with an invalid hold selection, the gaming system is configured to play an “invalid hold selection” sound. If the player presses PLAY a second (or subsequent) time, the gaming system is configured to play the “invalid hold selection” sound and display an “invalid hold selection” banner or message on a display. 
     For each re-spin round, there is a hold selection with optimal expected return to player. 
     As reels are held or unheld, a meter displays the expected return to player relative to the expected return for the optimally held reels. 
     The feature cannot be triggered again during the feature. 
       FIGS. 8 and 9  show an exemplary initial game outcome and a subsequent game outcome after the hold and re-spin. 
     As shown in  FIG. 8 , five reels  831 A- 835 A have been spun up with a selection of four symbols on each of the reels, such that a symbol display  830  contains twenty selected symbols. Current values are shown on the credit, bet, and win meters  851 ,  852 , and  853 , respectively. A screen  800  also includes a free game indicator  840 , which, in the exemplary embodiment, indicates that one free game remains. A message  810  at the top of the screen  800  instructs the player to hold or unhold reels by touching them until they make their selection, before pressing the play button (not shown) to spin the unheld reels. An indicator  820  indicates whether the hold selection is optimal. In this respect a slider  825 A is shown towards the left of the indicator  820  in  FIG. 8  because the player has yet to make a selection, and keeping all of the reels (an option available to the player) would represent a sub-optimal selection by the player. In the illustrated embodiment, positions further towards the right of the indicator  820  represent better selections. 
       FIG. 9  shows an exemplary screen shot  900  after the player has made their selections and the reels have been re-spun. In this respect, it will be noted that the slider  825 B is located at the far right of the indicator  820 , indicating that the hold selection made by the player was optimal. A held indicator  838  is displayed above each of the held reels, as selected by the player. It will be noted that each of the reels  831 A,  832 A, and  835 A is identical to that which was shown in  FIG. 8 . New symbols have been selected and displayed for each of the reels  833 B and  834 B. The displayed combination of symbols in  FIG. 9  have been evaluated by an outcome evaluator, and a prize has been awarded by incrementing the win meter  853  by 40 credits from 355 credits in  FIG. 8  to 395 credits in  FIG. 9 . 
     It will be understood to persons skilled in the art of the present disclosure that many modifications may be made without departing from the spirit and scope of the present disclosure, in particular it will be apparent that certain features of embodiments of the disclosure can be employed to form further embodiments. 
     It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art in any country. 
     In the claims that follow and in the preceding description of the disclosure, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the present disclosure.