A bishop is a piece used in the game of chess which is played on a board of square grids. A bishop can only move diagonally from its current position and two bishops attack each other if one is on the path of the other. In the following figure, the dark squares represent the reachable locations for bishop B1 form its current position. The figure also shows that the bishops B1 and B2 are in attacking positions whereas B1 and B3 are not. B2 and B3 are also in non-attacking positions