Go (game)
Two players, "Black" and "White", take turns placing a "stone" (game piece) of their own color on a vacant "point" (intersection) of the grid on a Go board. Black plays first. If there is a large difference in skill between the players, the weaker player typically uses Black and is allowed to place two or more stones on the board to compensate for the difference (see Go handicaps). The official grid comprises 19×19 lines, though the rules can be applied to any grid size. 13×13 and 9×9 boards are popular choices to teach beginners, or for playing quick games. Once placed, a stone may not be moved to a different point.
Go variants
Quantum Go is a Go variant which provides a straightforward illustration of interesting quantum phenomena. Players alternatively play pairs of go stones which are entangled, in the sense that each entangled pair of stones will reduce to a single go stone at some point in the game. A process of quantum-like collapse occurs when a stone is played in contact with one of the stones in an entangled pair.