sun

Sun (寸, pronounced roughly "soon") is a traditional Japanese measure of length, equivalent to 3.030 cm or 1.193 inches--1/10 of a shaku (尺), which is almost exactly 30cm or 1 foot. Traditional go boards are an integral number of sun thick, ranging from table boards at 2-sun, to legged boards between 4-sun and as much as 8.

Bu is 1/10 sun, so a 5 1/2-sun board would be referred to as "5-sun 5-bu" ("go-sun go-bu").

See Also: Equipment Dimensions