Which two-player board game was patented in 1971 by Goro Hasegawa?

'Othello' is a variant of the older game 'Reversi' (1883) and was patented in 1971 by the Japanese inventor Goro Hasegawa (1932-2016). It is played on an 8x8 uncheckered board by two players with disks or counters that are black on one side and white on the other. Players take turns placing the disks on the board with their colour facing up. Each disk must be laid next to an opponent's piece. If one or more of one player's pieces are flanked either side by the opponent's pieces, all of the pieces between these two are 'captured' and turned over to match the player's colour.

'Othello' differs from 'Reversi' in that the first four pieces go into the centre at the beginning of the game rather than the starting player deciding where to place the first disk. Unlike 'Reversi', which ends if a player cannot move, a player simply passes their turn to the opposition until they can make a move. The game ends when all the pieces have been played or neither player can move.

Hasegawa chose the name 'Othello' in reference to Shakespeare's play 'Othello, the Moor of Venice'. In particular, it refers to the conflict between the titular character and the play's main antagonist, Iago. The green colour of the board on which the game is played was inspired by Othello leading his men into battle in a green field.

In 1973, the first national 'Othello' championship was played in Japan. After the game was introduced to the western world, it became an annual world championship.