Nigiri is a Japanese go term (from the Japanese, lit. "grab", "grasp", "squeeze") adopted into English, referring to the procedure common in Japan at the beginning of an even game to decide who will play the black stones; the equivalent of flipping a coin to determine who kicks off a game of football. The steps are:
- The first player grabs (hence the name) a handful of white stones without showing them to the other player
- The second player states his guess as to whether the number of stones is "odd" or "even" by placing one or two black stones on the go board. (In Japanese, 奇数先 or kisuu-sen for odd, or 偶数先, guusuu-sen for even).
- The first player then places the white stones in his hand on the go board, arranging them in pairs to make it easy to see whether the number is odd or even.
- If the second player has guessed correctly, he takes Black.
At the beginning of a series of games, such as a seven-game championship series, or even just a series of games between friends in a club, nigiri will be used to determine who plays black in the first game; in succeeding games, the colors will alternate. After reaching a 3-3 tie in a championship series the players will re-nigiri to determine who takes what color in the last game.
In Korea and Japan, is there a similar procedure for private games? According to John Fairbairn, in at least some pro tournaments in China, colours will likely be decided by a public drawing of lots, since professional go is more of a spectator sport there.
The senior player (stronger or older) player is normally the one who performs the nigiri (takes the handful of stones); if neither player has obvious seniority, such as in a friendly club game, then the player sitting nearer the white stones does so.
Note that in Ing rules, the player who won the nigiri doesn't take black but chooses his color; due to the 8-point komi, most players choose white. Here's the relevant Ing rule:
- Choosing colors: In an even game, colors are chosen as follows. The older player takes a handful of white stones and his opponent guesses even or odd. If he guesses correctly, he can choose black or white. Otherwise, the older player chooses black or white.
Nigiri can also be used to choose things other than playing colour. For example in some tournaments it is used as a two-person tie-breaker. This scheme is easily extended to include a three-way tie-break:
- Each player grabs a handful of stones.
- Each player displays the stones in pairs.
- If there is an "odd one out" (one even against two odd or one odd against two even), the odd one out has won the nigiri.
- If all have the same (three even or three odd), repeat the process.
An alternative, albeit completely non-standard, way to determine who begins is the Pie Rule.
Pasky: Do we have any idea how old nigiri is? Did it appear only in Japan already, or does it come from old China? What method to decide who is white did they use in old China?
Mathematically, odd is a more likely outcome than even unless an infinite number of stones may be grabbed. This is because the natural numbers start with 1, an odd number. To illustrate, let’s look at the probabilities for even vs odd, as the largest possible handful increases:
Handful Size Range | Probability of Odd
You can see that the chance of getting odd only approaches 50% as the possible range of stones increases to infinity. For finite hand sizes, odd will never be worse than even and is often above 50%
To make the chances as close to 50/50 as possible, you must grab the largest handful you can. Alternatively, limit your selection to either one or two stones only and never a “random” handful more than two. The player grabbing a handful of white stones is at a disadvantage, and the player setting black stones down should always choose odd.
xela: I disagree, because none of those ranges (1-2, 1-3, 1-4 etc) actually represent my own "handful size range". When I grab a generous handful of white stones, I never grab just a single stone. I don't actually know how big my minimum handful is, but it would be something like 8 or 9 stones. If it's 9, then the above analysis is still valid, so nigiri for me would be biased towards odd (assuming uniform distribution of sizes). But if it's 8, then the bias goes the opposite way. Since I haven't bothered to keep a log of my nigiri handful sizes over the years, I honestly don't know which way the bias goes, the two are equally likely. Hence I can call it "unbiased". And this is all assuming a uniform distribution of sizes. In fact, my largest and smallest handfuls are both quite rare; it's closer to a normal distribution around some unknown mean. (Probably should be some kind of beta distribution if we're really going to do this properly.)
Patrick Traill: I wonder if you can point me to a place where I can get some sets (preferably finite) with infinitely many stones?
SAS: In Fernando Aguilar's account of his game against Hasegawa Sunao, he says: "Hasegawa looked at the players' presentation card and noticed that my date of birth was some months before his, so he passed the white stones to me to do nigiri." (This is just a rough translation - my Spanish is not very good, to say the least.) This shows how it is the older player who takes the handful of white stones.
In Hikaru No Go manga episode 14, the Go Go Igo mini-lesson at the end by Umezawa Yukari, she states that "The older person does nigiri" and has the older girl grab the white stones while the younger boy places one black stone saying "Odd first," or two black stones saying "Even first." If he is correct, he plays black.
In online games, the server can randomly choose who plays black.
Nigiri is, of course, also a type of sushi - specifically the little blocks of rice with topping balanced on them. It would be interesting to know whether it is the same "grab" meaning or not. JennyRadcliffe
The word nigiri is also found in the compound nigiri zushi, the kind of sushi created by a sushi chef squeezing a portion of rice between his left hand and right index and middle fingers.
Chris Hayashida: Yes, it is. It's the squeezing of the rice into the riceballs. When I think of onigiri, I think of the salted rice balls that I ate for lunch when I was a kid. That's also why it's easy for me to remember to nigiri with the white stones... who wants to eat a black rice ball?
Aschwin van der Woude: Nigiri when talking about sushi is actually short for nigirimeshi (握り飯). Nigiri (握り) means gripping something with your hand, and meshi (飯) is simply boiled rice. So when making a rice ball that way, it is called Onigiri (お握り).