# Even-sized Boards

Keywords: Equipment
18x18 board

lezogzog I was told that the only reason for not playing on even-sized gobans is the lack of tengen. This seems to cause problems with mirror go. Is this explanation sound ? Does anybody see another one ?

Skelley: Why would/should we play on an even-sized board? I don't realy see a good reason for not playing on an odd-sized board...

unkx80: Possibly also to prevent draws when using Chinese rules.

Acid?: The board default is 19x19 because: "There are on the Go board 360 intersections plus one. The number one is supreme and gives rise to the other numbers because it occupies the ultimate position and governs the four quarters. 360 represents the number of days in the (lunar) year. The division of the Go board into four quarters symbolizes the four seasons. The 72 points on the circumference represent the (five-day) weeks of the (Chinese lunar) calendar. The balance of Yin and Yang is the model for the equal division of the 360 stones into black and white."

From The Classic of Go?, by Chang Nui? (Published between 1049 and 1054)

Bildstein: Anyone want to try an 18x18 Ongoing Game? To make it even-ish, I'll play against any single digit kyu or stronger. First in, first served. Just to make it interesting, I'll play White, and I'll play mirror go.

PlatinumDragon: Wrong, the defualt board is 19x19 not because of the 360 whatever that people say, but that it is the largest odd sized square board with the 3rd line as a territory line. Each board range has a different territory line. In my post in "Why 19x19," I have explain that there is a function. I will not give out this function as it is only a simple algebraic function that anyone can derive. The 20x20 is the largest square board with 3rd line as territory line.

Even-sized Boards last edited by PlatinumDragon on April 4, 2009 - 03:29