Difference between revisions of "Nozoki"
m (Grammar and style.) |
(Fixed some factual mistakes. In the original examples, the nozoki wasn't true, or could be played later.) |
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<hexboard size="6x6" | <hexboard size="6x6" | ||
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| − | contents="B :d3 R :e4 B :e3 R :b3 B :b4 E *:c4 E *:c3" | + | contents="B :d3 R :e4 B :e3 R :b3 B :b4 E *:c4 E *:c3 R c2 d5" |
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In this position, Redr can play 2 '''correct nozokis''' — c4 or c3. If Red plays c3, Blue must defend with c4. If Red plays c4, Blue must defend with c3. Otherwise, Blue loses the game. | In this position, Redr can play 2 '''correct nozokis''' — c4 or c3. If Red plays c3, Blue must defend with c4. If Red plays c4, Blue must defend with c3. Otherwise, Blue loses the game. | ||
| − | Notice that moves at a4, a5, f2 and f3 are '''wrong nozokis'''. Against a4 or a5, Blue has a choice of playing b5 which improves Blue's position. Similarly, against f2 or f3, Blue should play d2. | + | Notice that moves at a4, a5, f2 and f3 are '''wrong nozokis'''. Against a4 or a5, Blue has a choice of playing b5, which potentially improves Blue's position. Similarly, against f2 or f3, Blue should play d2. |
== Crucial nozoki == | == Crucial nozoki == | ||
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| − | contents="B :h4 R :d4 B :e5 R :g6 B :c6 E *:d6" | + | contents="B :h4 R :d4 B :e5 R :g6 B :c6 R g4 B g5 E *:d6" |
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| − | The only winning move for Red is the nozoki | + | The only winning move for Red is the nozoki at d6. If Red misses it, the game proceeds as follows and Blue wins: |
<hexboard size="9x9" | <hexboard size="9x9" | ||
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| − | contents="B :h4 R :d4 B :e5 R :g6 B :c6 R | + | contents="B :h4 R :d4 B :e5 R :g6 B :c6 R g4 B g5 R 1:f5 B 2:f6 R 3:e6 B 4:d8 R 5:e7 B 6:e9" |
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| − | If Red starts by playing d6 instead, Red wins | + | If Red starts by playing d6 instead, Red wins. |
<hexboard size="9x9" | <hexboard size="9x9" | ||
coords="show" | coords="show" | ||
| − | contents="B :h4 R :d4 B :e5 R :g6 B :c6 R 1:d6 B 2:d5 R 3: | + | contents="B :h4 R :d4 B :e5 R :g6 B :c6 R g4 B g5 R 1:d6 B 2:d5 R 3:f5" |
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Revision as of 02:52, 30 November 2020
A nozoki (term borrowed from Go) is a forcing move to which opponent has just a single answer to defend against an immediate threat. This situation occurs if one threatens to cut a connection between major groups or key stones of the opponent. The stone causing this threat is called a nozoki.
Sometimes it's hard to tell if a move is forcing, i.e. if the nozoki is correct or wrong. Playing correct nozokis is one of the most sophisticated aspects of Hex strategy.
Example
In this position, Redr can play 2 correct nozokis — c4 or c3. If Red plays c3, Blue must defend with c4. If Red plays c4, Blue must defend with c3. Otherwise, Blue loses the game.
Notice that moves at a4, a5, f2 and f3 are wrong nozokis. Against a4 or a5, Blue has a choice of playing b5, which potentially improves Blue's position. Similarly, against f2 or f3, Blue should play d2.
Crucial nozoki
Playing nozokis can be very useful. In certain situations, playing a nozoki can make the difference between winning and losing. Consider the following example:
The only winning move for Red is the nozoki at d6. If Red misses it, the game proceeds as follows and Blue wins:
If Red starts by playing d6 instead, Red wins.
