is oshi-tsubushi, literally "squashing push", a Japanese term. See below [1] for translations.

After , White's connection at the marked point is an illegal suicide move under most rulesets. Later Black can capture the two White stones, gaining two eyes and life.

If Black misses the oshi-tsubushi and instead takes the ko with , White plays under at and Black will die. Taking with is useless; White throws in with 4 at and Black only has a false eye here. (If instead of White mistakenly treats this as a ko fight, making a ko threat and then retaking the ko, Black gets a second chance at oshi-tsubushi.)

Behavior under different rule sets

Under rulesets which allow self-capture, is possible; the three White stones are then immediately removed. If White can play at the point it would kill the black stones. now makes life, and so because Black must respond to attain it, the self-capturing move can be used as a ko threat.

Variations on the very first position on this page

The following related positions aren't examples of Oshi-tsubushi but may still be useful.

If it were White to play in the original position, he can kill Black by connecting at and forming nakade. If captures the three stones, White 3 at holds Black to one eye.

Oshi-tsubushi can be prevented by damezumari. In this position, Black's lack of liberties means that after he is still in atari.

Application in life & death situations

here doesn't understand the position. Now Black can live.

Black lives with the sacrifice and oshi-tsubushi at .

In this case, however, White can kill by creating a bent four in the corner.

English terms

^[1] There is no consensus on an alternative English term for Oshi-tsubushi. Robert Jasiek in his books uses internal liberty shortage for this kind of life and death tesuji. The everyday translations, crush, squash, and smash, are also occasionally seen. A related concept is Eye by exhaustion, a term coined by Tamsin.

Chinese terms

Word-for-word, the term 胀牯牛 (zhàng gǔ niú) could be translated as swollen or bloated cow. The general word for cow is 牛; 牯牛 can mean (female) cow, or castrated bull, or more generally can be like the English word cow in its loose or informal sense, as given by Wiktionary "Any member of the species Bos taurus regardless of sex or age, including bulls and calves".

Word-for-word, 胀死牛 (zhàng sǐ niú) could be "bloated dead cow".