======== Newsgroups: rec.games.go Subject: Goban dimensions, a summary From: crich@filenet.com (Charles Rich) Date: 29 Apr 2002 14:32:02 -0700 Using Google's search engine I read several years of postings to rec.games.go about goban dimensions, particularly the sizes of the playing grid. I figured that before making some inexpensive boards for work, home and my kids' school I might as well get it right. After finding a lot of variation among the many good postings here, I also visited the Seattle Go Center and measured three of the beautiful goban in their shoji enclosed, tatami playing room. These are real chunkers, about 6 to 8" thick with beatiful grain. Quite the traditional tables. And still there were variations among them. So here's the upshot, despite the Nihon Ki'in's ideal specs, even the finest boards show a lot of variation. I focused on the ratio of the longer dimension to the shorter since the length of the short side is pretty much driven by the diameter of the white stones. When available, I also noted the size of the border around the grid and that too has a lot of variation. Here's what I came up with, please note that all measurements are in centimeters: ---------------------------------------------------------------------------- Goban source Hborder Vborder H grid V grid Ratio ----------------------------------- ------- ------- ------ ------ ------ Seattle Go Center, board #1 0.90 1.20 39.50 42.95 1.0873 Seattle Go Center, board #2 1.55 1.55 38.54 42.12 1.0930 Seattle Go Center, board #3 1.25 1.50 39.50 42.55 1.0772 Yutopian spruce board (Korean) 1.75 1.90 39.33 42.00 1.0679 Nihon Kiin (ideal spec) 1.12 1.20 40.19 43.06 1.0714 Roy Schmidt (rec.games.go) 1.35 1.35 39.72 42.75 1.0763 Lasker (27/32" x 29/32" cell) 38.58 41.43 1.0741 Sensei's Library (22mm x 23.7mm cell) 1.38 1.38 39.60 42.66 1.0773 ---------------------------------------------------------------------------- Average ratio: 1.0781 Average (after casting out the two outlyers): 1.0773 ---------------------------------------------------------------------------- I used the size of the whole grid in order to eliminate small differences between individual lines and it let me measure more accurately by being larger. When only the cell size was given I obtained the whole grid size by multiplying it by 18. It is interesting to note that the Japanese goban have the largest ratios, suggesting a taste for a slightly longer board. My Korean Yutopian board has the smallest, and it is totally *fine*, so these differences are really small. After going over the ratios and casting out the single largest and the smallest, and then re-averaging, I came up with the ratio: 1.0773 which happens also to match Sensei's Library and one of the Seattle Go Center tables. That is the ratio I chose for my boards. I found a lot of variation in the border sizes too. Some are the same size on all four sides but most use a slightly larger border in the vertical dimension. I thought the same-sized border on the SGC board #2 looked very handsome and so I plan to use something similar too. Using a cell width of 2.2 cm gives a cell height of 2.37 and a playing grid of 39.60 by 42.66 cm. Since my average white stone is a little different, my dimensions will be a little different. Yours will too. Anyway I hope this helps the next poor soul who feels driven to come up with a good set of goban dimensions! Cheers, Charles Rich