Golden Chicken Standing on One Leg
Golden Chicken Standing on One Leg (金鸡独立 jīn jī dú lì) is the Chinese name for a set of positions in which one player uses a descent to split the opponent's stones into two groups such that the opponent commits self-atari should he attempt to capture the opponents stones. This tesuji can occur only at the edge of the board. It is a specific case of the more general double shortage of liberties.
The is problem 38 of Weiqi Rapid Drill 800 Problems (围棋快速练习800题). The solution is for Black to create the Golden Chicken Standing on One Leg shape by playing on the circled point. (黑 1 立 "金鸡独立", 白上下气紧均不入子, 黑突围成功.)
The is problem 99 of Weiqi Rapid Drill 800 Problems (围棋快速练习800题). By contrast, the solution is for Black to play at the circled point. If black gives atari from the other side, white will play there creating the Golden Chicken Standing on One Leg shape and kill Black. (黑 1 打方向正确. 黑 1 若在a位打, 白 1 位立则成 "金鸡独立".)