provided from the read only memory 6 the special code detector 501 increments the address of the memory address counter 55 and also disables the display buffer 51 this situation occurs in the case of the game problem that is in the case of the game problem the next position to place the next go stone is not indicated on the go game board by leds 13 so that the player try to consider the next move of the next go stone when the player put the next go stone on the go game board 2 the comparator 54 detects the placement of the stone in the manner as mentioned referring to fig6 and provides a stone detecting signal to an address comparator 502 this address comparator 502 compares the data of the sensor address counter 52 with the coded data from the read only memory 6 and if these two data are identical the imaginary board memory 53 is rewritten to the latest state of the developments of the game and the address of the memory address counter 55 is increased by the signal from the address comparator 502 and additionally the result of the identity is informed to the player by an informing unit 503 but if the result of the comparison is not identical the address comparator 502 instead of the above mentioned operation increases the false number of a false number counter 504 by the output signal of itself the controller 5 further comprises a number presettable unit 506 and a false number comparator 505 in the case that the result of comparison is not identical the false number of the false number counter 504 is increased.