FiveHundredAndOneTesujiProblems/Problem113Solution

Diagram 1  

Answer to Problem 113 (guzumi) Black secures his stones in the corner by connecting with 1 in Diagram 1.

Diagram 2  

Descending to Black 1 in Diagram 2 seems to adequately defend the corner, but White can attach with 2 and draw back with 4. Black needs another move to secure two eyes for this stones or else clamping toi the the left of 3 will leave Black's stones with only one eye.

Note: Each of the moves in diagram 2, in the proper circumstances, could be tesuji. Each is named (sagari, shita-tsuke, hane, hiki) and listed in the book's glossary of tesuji.