Tsumego From Games 138 / Attempts

Black to play & kill the upper right group  

In the actual game, I played at thinking it was a Vital Point, but after white gets a ko. Black can do better.

unkx80: But has the option of playing at a to capture five White stones in a connect-and-die. While not the best possible result for Black, it is still a disaster for White locally.

DrStraw: Not only that, after B takes the 5 stones W still will not be able to connect the other two stones, so they are dead also. Of course, the correct answer is still better.