A grid of 19x19 lines, giving 361 playing points where lines intersect (AGA Rule 1); Smaller boards are permitted, 13x13 and 9x9 being the two most common (AGA Rule 1); Nine marked points (star points or hoshi) are used to place handicap stones (AGA Rule 4)
Why people argue about this
People often assume that the 19x19 grid is a mandatory requirement for all games of Go (AGA), but actually, smaller boards like 13x13 or 9x9 are explicitly allowed and are commonly used in different levels of play, including handicap matches where players start with fewer stones.
