![]() StartingPoints Paths Referenced by
|
Oiotoshi
Difficulty: Beginner
Keywords: Tesuji, Tactics, Go term
Oiotoshi 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 is to extend, and that the resulting group still is in atari. The term 'oiotoshi' also describes the process of setting up such a situation. Here's an example (modified from the Second Book of Go:
Black 1 starts the oiotoshi. If White tries to run away at 2, Black 3 is atari again, and this time running away at 4 doesn't help White at all since now the whole group is in atari at 'a'. So White shouldn't have run away at 2, but instead connected at 'a' or 4.
Using the previous example as reference, it is easy to see that if White saves his two circled stones here, black can capture the White stone with a square; blocking off white's progress along the top side. Black 1 is also called oiotoshi. (I'm not sure whether this example is relevant enough (and correct)! Comments, please. -- Jan) BillSpight: B 1 is premature. It requires the atari (circled) below.
I don't think this is premature. Doesn't this work? (Thomas Nordhaus)
Bill is right, in the starting position the "tesuji" is premature and brings almost nothing (Capturing one stone will be a bigger sente than if 1 hadn't been played, but on the other hand, one ko threat has been lost). White should of course connect at 4 and black can capture only one stone which he can capture without sacrificing at 1 anyway. -- AlainWettach
Bill:
After B 1, W 2 is White's correct response. If White does not play there, Black can throw in at 6. After W 2, B 5 and W 6 are miai. Black can count 1/3 point in the ko (1/3 of the marked stone).
W 6 fills at 1. Oiotoshi is also known under the terms 'connect and die' and 'serial atari'. See also: Damezumari and Throw In. The Crane's Nest is a classic example of oiotoshi. -- Jan de Wit This is a copy of the living page "Oiotoshi" at Sensei's Library. (C) the Authors, published under the OpenContent License V1.0. |