Slot machine and playing method thereof

Abstract

A slot machine is operable to cause, when a sub game in which a specific symbol is selected from among a plurality of symbols by an external input was executed, a predetermined number of times of special game as a unit game to be executed after the sub game, vary a payout amount of credits in accordance with the appearance frequency of the specific symbol on a main display during the special game, and display the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency on the sub display.

1 . A slot machine comprising:
 a main display on which a plurality of symbols that have been arranged are rearranged in a unit game;   a sub display on which an appearance frequency of a specific symbol and a payout amount of credits in accordance with the appearance frequency are displayed; and   a controller operable to:
 (a) when a sub game in which a specific symbol is selected from among the plurality of symbols by an external input was executed, cause a predetermined number of times of special game as a unit game to be executed after the sub game, 
 (b) vary the payout amount of credits in accordance with the appearance frequency of the specific symbol on the main display during the special game, and 
 (c) display the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency on the sub display. 
   
   
   
       2 . The slot machine according to  claim 1 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of specific symbols rearranged on the main display during the special game. 
   
   
       3 . The slot machine according to  claim 1 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of times the specific symbol is rearranged on the main display during the special game. 
   
   
       4 . A slot machine comprising:
 a main display on which a plurality of symbols that have been arranged are rearranged in a unit game;   a sub display on which an appearance frequency of a specific symbol and a payout amount of credits in accordance with the appearance frequency are displayed; and   a controller operable to:
 (a) when a sub game in which a specific symbol is selected from among the plurality of symbols by an external input was executed, cause a predetermined number of times of special game as a unit game to be executed after the sub game, 
 (b) vary the payout amount of credits in accordance with the appearance frequency of the specific symbol on the main display during the special game, 
 (c) increase the payout amount of credits in accordance with the appearance frequency of the symbol more than that of the symbol having a larger expectation value of payout when the specific symbol is a symbol having a small expectation value of payout, and reduce the payout amount of credits in accordance with the appearance frequency of the symbol less than that of the symbol having a smaller expectation value of payout when the specific symbol is a symbol having a large expectation value of payout, and 
 (d) display the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency on the sub display. 
   
   
   
       5 . The slot machine according to  claim 4 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of specific symbols rearranged on the main display during the special game. 
   
   
       6 . The slot machine according to  claim 4 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of times the specific symbol is rearranged on the main display during the special game. 
   
   
       7 . A slot machine comprising:
 a main display on which a plurality of symbols that have been arranged are rearranged in a unit game;   a sub display on which an appearance frequency of a specific symbol and a payout amount of credits in accordance with the appearance frequency are displayed; and   a controller operable to:
 (a) when a sub game in which a specific symbol is selected from among the plurality of symbols by an external input was executed, cause a predetermined number of times of special game as a unit game to be executed after the sub game, 
 (b) vary the payout amount of credits in accordance with the appearance frequency of the specific symbol on the main display during the special game, 
 (c) increase the payout amount of credits in accordance with the appearance frequency of the symbol more than that of the symbol having a larger expectation value of payout when the specific symbol is a symbol having a small expectation value of payout, and reduce the payout amount of credits in accordance with the appearance frequency of the symbol less than that of the symbol having a smaller expectation value of payout when the specific symbol is a symbol having a large expectation value of payout, and 
 (d) update the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency each time each special game is over or the specific symbol is rearranged on the main display, and display them on the sub display. 
   
   
   
       8 . The slot machine according to  claim 7 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of specific symbols rearranged on the main display during the special game. 
   
   
       9 . The slot machine according to  claim 7 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of times the specific symbol is rearranged on the main display during the special game. 
   
   
       10 . A playing method executed in a slot machine, comprising the steps of:
 (a) causing a controller to rearrange a plurality of symbols that have been arranged on a main display in a unit game;   (b) when a sub game in which a specific symbol is selected from among the plurality of symbols by an external input was executed, causing the controller to execute a predetermined number of times of special game as a unit game after the sub game, and to vary the payout amount of credits in accordance with the appearance frequency of the specific symbol on the main display during the special game; and   (c) causing the controller to display the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency on the sub display.   
   
   
       11 . The playing method executed in a slot machine according to  claim 10 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of specific symbols rearranged on the main display during the special game. 
   
   
       12 . The playing method executed in a slot machine according to  claim 10 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of times the specific symbol is rearranged on the main display during the special game. 
   
   
       13 . A playing method executed in a slot machine, comprising the steps of:
 (a) causing a controller to rearrange a plurality of symbols that have been arranged on a main display in a unit game;   (b) when a sub game in which a specific symbol is selected from among the plurality of symbols by an external input was executed, causing the controller to execute a predetermined number of times of special game as a unit game after the sub game, and to vary the payout amount of credits in accordance with the appearance frequency of the specific symbol on the main display during the special game;   (c) causing the controller to increase the payout amount of credits in accordance with the appearance frequency of the symbol more than that of the symbol having a larger expectation value of payout when the specific symbol is a symbol having a small expectation value of payout, and to reduce the payout amount of credits in accordance with the appearance frequency of the symbol less than that of the symbol having a smaller expectation value of payout when the specific symbol is a symbol having a large expectation value of payout; and   (d) causing the controller to display the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency on the sub display.   
   
   
       14 . The playing method executed in a slot machine according to  claim 13 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of specific symbols rearranged on the main display during the special game. 
   
   
       15 . The playing method executed in a slot machine according to  claim 13 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of times the specific symbol is rearranged on the main display during the special game. 
   
   
       16 . A playing method executed in a slot machine, comprising the steps of:
 (a) causing a controller to rearrange a plurality of symbols that have been arranged on a main display in a unit game;   (b) when a sub game in which a specific symbol is selected from among the plurality of symbols by an external input was executed, causing the controller to execute a predetermined number of times of special game as a unit game after the sub game, and to vary the payout amount of credits in accordance with the appearance frequency of the specific symbol on the main display during the special game;   (c) causing the controller to increase the payout amount of credits in accordance with the appearance frequency of the symbol more than that of the symbol having a larger expectation value of payout when the specific symbol is a symbol having a small expectation value of payout, and to reduce the payout amount of credits in accordance with the appearance frequency of the symbol less than that of the symbol having a smaller expectation value of payout when the specific symbol is a symbol having a large expectation value of payout; and   (d) causing the controller to update the appearance frequency of the specific symbol on the main display and the payout amount of credits in accordance with the appearance frequency each time each special game is over or the specific symbol is rearranged on the main display, and to display them on the sub display.   
   
   
       17 . The playing method executed in a slot machine according to  claim 16 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of specific symbols rearranged on the main display during the special game. 
   
   
       18 . The playing method executed in a slot machine according to  claim 16 , wherein the controller is operable to increase the payout amount of credits in accordance with the increase in the number of times the specific symbol is rearranged on the main display during the special game.