Why are the boards not square?

I noticed gobans are not square, but rectangular. Why is that, and what is the correct orientation of the board when playing?

• By the way, what happens if you put a really square goban in front of a go player? He will turn it by 90 degrees, then turn it again, then stare intently on it, then laugh, and finally put it in the direction of the wood grain (if any).
– Svante
Nov 14, 2011 at 1:31
• @svante : haha ! Excellent :) Dec 7, 2011 at 10:17

4 Answers

The design of Go components is all about symmetry. Because perspective shortens the vertical height of the board, the boards are made taller than they are wide. This way they appear to be square when you're playing. Another similar issue occurs with the stones. Black stones appear to be smaller than white stones, so the black stones are actually made slightly larger than the white stones to counter this effect.

Related and awesome: How many squares are there on a Go Board?

• A fun fact: go applications usually use rectangular boards as well (preserving the letter but not the intent of tradition). This has the peculiar effect of making internet-bred players stand up during live games to make the board look more like their native environment.
– vertigo
Nov 14, 2011 at 20:38
• That's funny, vertigo. I've had opponents do that in person but never realized the reason. I can assure you, GoGrinder's boards are square, so they will help to break this habit :P
– TimK
Nov 14, 2011 at 20:55
• @vertigo Which go programs have non square boards? KGS for example is square. As an online player, my problems with real boards were mainly imperfect stones placement and the perspective, not seeing stones from the top. Nov 16, 2011 at 11:01
• @CodesInChaos my SGF viewer app (Qipan, for iOS) has non-square board. It simply looks wrong if it is square ;-)
– ohho
Dec 5, 2013 at 3:47

This is apparently to combat an optical illusion that "flattens" a board in front of you (as perspective narrows it towards the "horizon"). Therefore, the correct orientation is with the shorter edges in front of the players.

My japanese goban is exactly like that (45x42 cm²) and the effect it's actually noticeable after you have been playing for a while.

However, I also own a korean folding goban which is a bit smaller (understandably as it is supposed to be easier to carry around, with accordingly slightly smaller nice glass stones) which is exactly 38.5x38.5 cm², and although I cannot now find the reference (looked over the Internet and my books) I actually recall reading that Korean boards are usually squared instead of rectangular; maybe someone can find a source for this.

Anecdotically, our go club Sensei (a Japanese ex-insei) once really called us out in the middle of a game cause we had inadvertently put the goban the wrong way. It was amusing and embarrasing. So much, that in the end we called it a jigo, turned the board 90º and started a new game!

He actually nodded with his head and smiled the next time he came by to have a look.

• You know, you can turn the board 90º without starting a new game :) It won't affect play at all.
– Adrian Petrescu
Nov 16, 2011 at 9:09
• @AdrianPetrescu Haha, I would have missed that too :)
– mafu
Nov 16, 2011 at 10:38
• :-) Of course we knew, but once you get used to see the shapes in one direction, rotating felt so weird we decided it was easier to start a new game... It was Friday night, after all, we were cheery :-)
– Excalibor
Nov 16, 2011 at 21:44

Indeed it has to do something with perspective, but a full compensation for perpective would require a much more stretched board.

I believe the squares are stretched just enough so that vertically adjacent stones appear to be touching and not overlapping (consistent with horizontally adjacent stones). In that way, thicker stones require a deeper board than thinner stones.

• Interesting. Is that really the case? I figured it appears more or less completely square by just the slight width adjustment already.
– mafu
Nov 16, 2011 at 10:39
• Mafutrct: here's a picture of a goban from a typical view angle. It is much less high than it is wide. 4.bp.blogspot.com/_-qF6CbJo2vY/SGtlBGDCJGI/AAAAAAAAChs/…
– Kris Van Bael
Nov 16, 2011 at 22:22
• Note that this is a CG image. I don't trust CG images for this sort of thing at all, and in fact think the image may be wrong here
– mafu
Nov 16, 2011 at 23:48