Oiotoshi

Paths: <= Mistake =>   ·   <= Tesuji =>   ·   <= Give me liberties =>
  Difficulty: Beginner   Keywords: Tesuji, Tactics, Go term

Chinese: 接不归 (jie1 bu4 gui1)
Japanese: 追い落とし (oi-otoshi)
Korean: 촉촉수 (chokchoksu)

Table of contents Table of diagrams
Oiotoshi
Connect and die
Oiotoshi
Oiotoshi
Oiotoshi

Oi-otoshi (追い落とし, chasing and capturing, or, perhaps, chasing down), a Japanese go term, describes a situation where a stone or group of stones is put into atari in such a way that there is no escape. This occurs usually when the only way to save such a group temporarily is to connect, and that the resulting group is still in atari. Hence the related English terminology, connect-and-die, and the Chinese 接不归 (jie1 bu4 gui1) (unable to connect back).

The term oiotoshi can also describe the process of, or preliminaries such as throw-ins, setting up such a situation.

Oiotoshi is also known under the terms connect and die and serial atari.

Please note: oi-otoshi differs from connect-and-die in one way. Oi-otoshi is a form of sacrifice, a method of destroying eye shape, or using shortage of liberties to prevent connection while connect-and-die only covers shortage of liberties. It also reflects the opposite point of view.


Example 1

[Diagram]
Oiotoshi  

After W1, the three marked stones are under atari. However, if black tries to save the three stones by connecting with a, then white captures everything with b. Hence, the three marked stones are effectively captured and we say that these stones are caught in a connect and die.


Example 2

(from IGS)

[Diagram]
Connect and die  

The three Black black+circle stones are captured in connect-and-die.


Example 3

(from IGS)

[Diagram]
Oiotoshi  

After throwing in twice with W1 and W3, White ensures life by connecting at W5. Black can not save all his stones.

(This is Oiotoshi Problem 1 in Segoe and Go Seigen's Tesuji Dictionary.)


Example 4

(modified from The Second Book of Go)

[Diagram]
Oiotoshi  
[Diagram]
Oiotoshi  

B1 starts the oiotoshi. If White tries to run away at W2, B3 is atari again, and this time running away at W4 doesn't help White at all since now the whole group is captured.

So White shouldn't have run away at W2, but instead connected with W5.


spazdor: I would like to propose another name for this: "catching the lizard by its tail."

Some types of lizards, when caught by their tails, will allow the tail to fall off so that they may escape, leaving the wriggling tail behind to confuse predators.


See also


Paths: <= Mistake =>   ·   <= Tesuji =>   ·   <= Give me liberties =>
Oiotoshi last edited by marioxcc on May 10, 2015 - 04:47
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