Miai

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  Difficulty: Intermediate   Keywords: Tactics

Chinese: 见合 (jian4 he2)
Japanese: 見合い (miai)
Korean: 맞보기 (mat bo ki)

Table of contents Table of diagrams
Miai (life and death)
Example 2 (a)
Example 2 (b)

Definition of miai

The Japanese go term, adopted into English, miai denotes that there are two different options such that, if one player takes one, the other player can take the other. Also, it typically does not matter which player gets which option, but sometimes each player has only one of the options.

Examples

[Diagram]

Miai (life and death)

For example, in this diagram White lives because if Black plays at a, White plays at b; and if Black plays at b, White plays at a, in both cases making two eyes. Unless Black plays here as a ko threat, we expect that this position will remain until the final stage of the game, when one player will get a and the other will get b, even if White plays first.

We say that a and b are miai for two eyes. In general any such situation where when one player takes or prevents one of two options, the opponent will play the other, is called miai. In English, the points are sometimes said to reflect each other. (Think of a see-saw.)

This might be the case in a local position like this, but also in more general, strategic concepts. For example, if Black has a large moyo which White can reduce or invade from two sides, the two invasions might be miai. For another good example of miai, see wariuchi.

[Diagram]

Example 2 (a)

If Black plays B1, White plays W2, for a net local score of zero.

[Diagram]

Example 2 (b)

Or White may play W1 and Black B2, also for a local score of zero.

We expect one player to get one play, the other player to get the other, for a net local score of zero. The plays are miai.

Equivalence

Note that equivalence is an important aspect of miai. In miai positions, both the points are about the same in value, but they may not be exactly the same.

Usually, it is better not to play out miai points without additional reason. For example, in the situation above, a black move at a or b is sente. But playing it in the middle game is a loss of a ko threat which might prove to be decisive for the outcome of the game.

kritz An associate from Japan informed me that this also means "arranged marriage." We need to be careful with this one I think.

Clarification The word for arranged marriage uses the polite prefix: omiai. See also: [ext] http://en.wikipedia.org/wiki/Miai


See also:

Contributors:

This page was Wiki Master Edited by Dieter from the old page.


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