I had a heavy book which introduced tons of games of all kinds when I was a kid. I was fascinated by go back then. Now, about 15 years later I am actually getting to know the game. I was doing some tsumegos from the Cho Chikun’s Encyclopedia of Life and Death when the 21st tsumego caught my attention. The objective is to kill a stone chain in the corner. I considered all options and I came into conclusion that the stones cannot be killed. Although of course they can be killed.
I discovered that playing into the corner is the correct solution, but I am still puzzled why it is. White responds by connecting his stones on the 2-5-point and then what? To me it looks like a seki situation, mutual life. The chain of three black stones and the white chain have mutual liberties on S1 and T4.