Goban dimensions, a summary
Charles Rich
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:
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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
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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
D. Spy
the stones? That way I can measure the white stone in order to
get the ideal size for the grid.
Donald
Charles Rich
I'm sure I'm just being overly fussy on that point, fiddling with it
just because it was easy to. Most stones will be so close to 22mm
that I would just go with that. That way your board will still look
good with any other stones you might play on it too.
I had measured some of my white yuki's and found that they ran a hair
smaller (even varing by +-0.005 among individual stones) but as long
as I had that number I based my board on it. I used a graphics
program to print a set of tick marks which I made my lines from, so it
was easy to plug in my actual value. The difference is really
negligible though.
If you buy an unusual size of stone though, say significantly smaller,
I would definitely base the board on their measure then.
Good luck!
Charles Rich