Why are there 64 squares on a chessboard?

My question is, why not 36, 49, 81 or some other square number? Do any historical sources point to how and why chess came to be played on 64 squares in particular? Has it always been so?

• It's interesting that the board, Ashtapada, is probably much older than the game of chess itself. – Dag Oskar Madsen Jun 20 '15 at 13:04
• This was invented in india – Bugfixer Jun 20 '15 at 13:08
• What shape would you use for a 32-square or 128-square board, since those aren't square numbers? Instead of 2^5 and 2^7, you instead probably want to be asking about different n^2 possibilities for various values of n besides 8. Your question as originally written has already received several votes to close, and I'd be inclined to vote that way as well. But I've taken the liberty of editing it into a form that might be less inviting to opinionated answers (and changed to ask about n^2 values instead of 2^n), to see if there's a question here that the community will keep open. – ETD Jun 20 '15 at 15:38
• I don't really understand the point of the Edit. Why is it a given that the board has to be square? There are 10x8 chess variants and it is a sensible question, whether 8x8 is the board of choice for purely historic reasons or whether there are some intrinsic advantages of this size and shape. – BlindKungFuMaster Jun 22 '15 at 8:47
• @BlindKungFuMaster, the main point of the edit was to make it an historical question rather than purely opinion-based, so it could remain open. As for the quantitative change, the emphasis on squares is indeed not entirely essential; primarily I was acting on a speculative hunch that the OP intended to ask about different square sizes and had made a typo. After all, it's pretty plausible intuitively that 64 being a square number has more to do with it being the size of the standard chess board than that it's a power of 2. – ETD Jul 5 '15 at 14:11

5 Answers

Nothing is stopping you from playing chess in a 4x4, 6x6 or 9x9 board. In ancient times people have tried such approaches.

To answer why 64 squares, I have to answer a bit mathematically. Let me start with this:

[Chess, in] its early form in the 6th century was known as chaturaṅga, which translates as "four divisions (of the military)": infantry, cavalry, elephantry, and chariotry.

It says that chaturanga means 'game of squares' and it also mentions 4 divisions of military, where 1 division = 8 pieces (4 pawns + 4 main pieces). So 4x4 = 16 pieces each side. This also means, all in all, a total of 32 pieces in the board (8 in each row).

For 32 pieces to be fully mobile on the board, 36 squares would be too congested and not possible; 49 squares would be still too congested; 64 sure makes sense, and is also the perfect square of 8.

Capablanca advocated for a 10x10 chess board. He was concerned that chess was getting played out, that there were far too many draws, so his response to that problem was to create two new pieces and play the game on a 10x10 board with ten pawns and ten pieces.

Eight, being a power of two, makes for an easily drawn board:

1) Start with a big square. 2) Divide that square in half, both vertically and horizontally. (result: 4 squares.) 3) Divide each of the resulting squares in half similarly. (Result: 16 squares.) 4) Divide each of those squares in half similarly. (Result: 64 squares.)

Successively dividing larger squares in half is fairly easy for the eye to do, without the aid of any sort of measuring device. If you want more precision, you can use a string tied around a marker (pencil, chalk, whatever) and a straightedge and make a 64-square chess board with almost as much precision as someone using a high-precision ruler. You couldn't do that for any size of board that isn't a power of two.

• Just what pieces would Capa have added? – yobamamama Jan 10 '20 at 18:32
• @yobamamama as a complement to the queen combining rook and bishop into one piece, he would include two other "combination" pieces: the archbishop, combining bishop and knight, and the chancellor, combining rook and knight. This variant is to be played on a 10x8 board, rather than a 10x10 board, but that is a minor detail. – Scounged Jan 10 '20 at 23:32

64 is a whole square, so that it is as wide as it is long.

It happens that it is also THE MOST suitable option for a chess game, because:

1. It is big enough to allow multiple maneuvers and strategical possibilities.

2. It is small enough to let general guidelines be formed.

3. The back-rank pieces (2 rooks, 2 knights, 2 bishops, 1 queen, 1 king) also necessitates a 8-row board. If you wanted to make it 81 (9x9) pieces board, you will have to add another piece (an extra queen?). But on such a big board, each game would at least require 30 minutes to finish, if not more. Blitz and bullet chess would not be an option.

4. IF there were 128 or 32 squares, you would be asking "Why this number of squares? Why not its double or half?" It is like asking, why does a right angle contain 90°?

• YoustayIgo, just giving you a heads up that the question has now been edited to be rather different (in hopes of avoiding closure), in case you want to alter your answer in any corresponding way. – ETD Jun 20 '15 at 15:54
• Shogi is played on a 9x9 board. The games take longer mostly because the pieces are weaker/slower. Blitz and bullet is entirely possible. – BlindKungFuMaster Jun 22 '15 at 8:49
• And why would not blitz be possible? You can play any game at slow or fast time rates – yobamamama Jan 10 '20 at 18:33

We should ask the inventors :) I think that they were playing another game on a 8x8 board (chaturanga?) and were lacking one or 2 players. Could also have been 10x10 (draughts), 19x19 (Go), 9x10 (Chinese chess with 18 pieces each), or any other number of fields.

• ... or standard Shogi with 81 squares, or Chu Shogi with 144 squares ... it is just an historical accident, I'd say – jk - Reinstate Monica Jun 25 '15 at 15:18

I think Chaturanga grew up at a time when there were three kinds of auxiliary troops: elephants, cavalry and chariots, which were deployed on the wings. With one general, that makes 7. However an odd number would mean that the elephants of one side are on the same colour square. So one can rationalise eight as the sweet number. However Chinese chess is 9x10 and Japanese Chess is 9x9 so what do I know?