Why does this need to be in a page of its own? Would it not be better as a small footnote on the Nigiri page?

Robert Jasiek: Guessing odd is better. The number of stones in one's hand is finite and the smallest possible number, one, is odd. Therefore on average an odd number occurs more frequently than an even number.

Herman Hiddema: I recently saw a player grab zero stones. He reached into his bowl, seemed to grab a handful, but did not actually take any stones. His opponent wrongly guessed odd (he had heard you should always guess odd, due to the reason you give above). :-)

MrTenuki: Robert-- since you're the rules expert, would you mind about giving a more formal mathematical proof for that? I'm asking because it seems to me that the logic of pairing up the numbers and leaving 1 as the odd one out only works for a non-infinite list. On the other hand, if there is proof that the maximum capacity of Go stones that an average person can fit in one palm is odd (and that 0 stones is not allowed), then your conclusion might be correct assuming that we have a uniform distribution of all possibilities.

Herman: If i generate a uniformly distributed number in the range 1..X, where X is the maximum number of stones that will fit in a players hand, then if X is even I have a 50-50 chance of getting even/odd. If X is odd then I have a slightly higher chance of getting odd. Since X depends on the player's hand size, it has a 50% chance of being odd, hence over many games a choice of odd would have a slightly bigger chance. Of course, in practice the distribution is unlikely to be uniform. It is probably a different statistical distribution. The only way to know would be to gather data, have a large test group grab hands of stones and count them.