Pivotal stones

   

Chinese: 要子 (yo zǐ)
Japanese: 要石 (kaname-ishi, yōseki)
Korean: 요석/要石 (yosoek)

Pivotal stones, also known as key stones or sometimes called cutting stones, are stones that separate two of the opponent's weak groups. A go proverb says, Do not sacrifice pivotal stones.

Pivotal stones are important because if they die, the enemy forces are joined up; if they live, the enemy remains divided and subject to separate attack. Not correctly distinguishing cutting stones from non-cutting stones is a typical beginner mistake.

Pivotal stones is a direct, character-by-character translation of the Japanese kaname-ishi, which as a compound also means keystone (of an arch).

Non-pivotal stones, junk stones, or kasu-ishi in Japanese, have a corresponding proverb: Do not run away with junk stones.

Example 1

[Diagram]
Moves 94 to 101  

Here is an example from Go World 105, p. 15, Yu Bin vs. Cho U, 9th LG Cup, Game One. Discussing W1, the commentary says "Players proud of their fighting strength would probably attack with W1 and W3 in the diagram without even thinking. But if White cuts at W5, Black counters by pushing out at B6. If W7, B8 captures the pivotal stones."

/Question


Example 2

[Diagram]
Variation 3  

From [ext] The Magic of Go, #62. The game is from the 1999 European Fujitsu Finals. The commentary states: "If Black 67 is played at 1 in Variation 3, Black will have no real answer after white 6. If black 7, white 8 puts Black on the spot making miai between capturing the marked stones and the pivotal stones at 3 and 5."


Pivotal stones last edited by Dieter on June 26, 2008 - 18:22
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