Thursday, October 27, 2011

Goté and senté

This small section (from a Wikipedia article) describing two Go terms shows why I love Go so much. You don't have to know much about Go to understand it. It shows the kind of tactical and strategic encounters one sees during a Go game that makes it so much fun and also so useful for teaching one skills in everyday-life decision making. The last two paragraphs are especially interesting to me.

(Note: the terms goté and senté are pronounced as "go-teh" and "sen-teh" respectively.)
A move that leaves the player an overwhelming follow-up move, and thus forces the opponent to respond, is said to have "sente" (先手), or "initiative"; the opponent has "gote" (後手). In most games, the player who keeps sente most of the time will win. 
Gote means "succeeding move" (lit: "after hand"), the opposite of sente, meaning "preceding move" (lit: "before hand"). Sente is a term to describe which player has the initiative in the game, and which moves result in taking and holding the initiative. More precisely, as one player attacks, and the other defends in gote, it can be said that they respectively do and do not have the initiative. 
The situation of having sente is favorable, permitting control of the flow of the game. Applying these concepts to a whole sequence is basic to higher strategy. If Black starts a sequence that properly ends in an even number of plays, Black retains sente in doing this. If Black starts a sequence that properly ends after an odd number of plays, Black loses sente and takes gote. 
Accepting gote should only be in return for some profitable exchange. Correct play in the yose (endgame) can consist of playing available sentesequences, and then taking the largest gote sequence on the board. That description is a simplification, though. A reverse sente play is a special type of gote play, preventing the opponent from making some sente move. The relative value of reverse sente plays depends on the overall position, but one can count it as twice the value of what it would be if purely gote. 
A player has sente if he does not currently need to respond to moves made by his opponent. This can be achieved by tenuki (ignoring the opponent), as a kind of gambit. A player can break out of gote, and can gain sente, by choosing to accept some future loss, on the local level, in order to take the initiative to play elsewhere. 
In the case that neither of the players directly respond to each other's moves, the game can become difficult. Both players will have sente on their turn, and the moves they are making are gote. This will likely end in large exchanges, or one player will be shown to have a weaker position, and will have to start answering to avoid heavy damage.


e said...

how does one decide which player goes first?

Certified Ashkenazi said...

Black goes first at the beginning of the game. Because white is somewhat at a disadvantage due to going second, after a certain point in history, white was given an automatic bonus called komi (nowadays, usually 6.5 points).

If people are of a different strength, then the weaker player is black and is usually given a handicap (he can place from one to nine stones on the board on set points; the number of stones depends on the difference between the players).

If players are of equal strength, then one of the players takes a few stones of one color in his hand and holds them in the fist. The other player guesses whether the first player had even or odd number of stones (he places two or one stones on the board to indicate his guess). Then the first player reveals his stones. If the second player guessed right, he gets black. If he guesses wrong, the first player gets black.

Certified Ashkenazi said...

But the point of sente and gote is not who goes first; the point is that a given move can either be such that it must elicit a defensive response (because if one does not counter it, one will be even more worse off) or not. If it is, then it is sente and the response is gote (for the other player).

In chess, an example of such a move is an attack on the queen. Even though, according to the rules of the game, one is allowed not to move or shield one’s queen when it’s attacked, in most cases it’s not advisable, since losing one’s queen is costly. So, an attack on the queen is sente and the opponent’s moving of the queen away is gote.

Now, in response to you attacking my queen, I can attack your queen. This way, I choose to respond to your sente not with a gote, but with a sente. You can choose to respond to it with a gote (move your queen), or continue your original sente sequence (take my queen), in which case we’ll end up trading loses.

In go, however, it’s a little more complicated than in chess, because the board is much bigger (about four times), so there is more strategy involved (chess strategy is more like tactics from the point of view of go). Also, because all pieces are of equal value, you’re trading off chunks of territory and/or influence for other chunks of territory/influence elsewhere.

Certified Ashkenazi said...

Actually, it’s 5.6 times bigger, because each region is nine by nine, and there are four regions.

micha said...

I enjoy sort-of Go. And the concept of Go even more.

Peirush "sort-of Go": I never found an opponent, so I play it against software. As anyone who tried Go playing programs knows, the quality of such software is uniformly poor. So, I have yet to develop the skills. But it's a fun puzzle-game, an alternative to my [employer's] b-berry's Rush Hour clone.

The idea of Go, that one needs to see the big picture as well as all the details, is the difference between Benei Aliyah (the Litvishe Mussarniks' term for what they and Chassidim shared in common) and stam being frum.

menachem said...

Did you know there's a proposition to make a stackexchange site for the game of Go, see here:

Certified Ashkenazi said...

micha, you can play with other people on KGS server.

You can also watch their games, read the comments, and, if you sign up for KGS Plus, get teaching games, etc.

You can download the client or just click on Play Now. Then sign in as a guest, register, etc. The instructions are on the site.

There are also Yahoo Games, but I like KGS much more.

menachem, I don't know what stackexchange is.

Certified Ashkenazi said...

Also, if you have Androir, the Go program from AI Factory Limited is actually pretty good (in terms of AI, interface, etc.), once you get to level 4 or so. I play against it when I am sitting at the red lights and when I am not listening to Chassidus.