Two sets of lens-shaped stones, one black and one white; A full set is 181 black and 180 white — enough to fill all 361 points, with Black holding the extra stone as Black plays first; Stones are placed on the intersections, including edges and corners, never inside the squares
Why people argue about this
People often assume that the stones can be placed inside the squares as well, which is incorrect according to the official rules — they must always sit on intersections, including edges and corners, never inside the squares themselves. This oversight leads to many disputes over where exactly the stones should be positioned during a game.
