Therefore Black tries the hane at . Sometimes it is a technique to live, but here, is more like a trick play. Here falls into the trap, allowing to play the sente move described above, aiming to live with a. If tries to kill, then captures the stone and connects outside.
From all the above discussion, it should be clear that the solution is for White to simply retreat from to , not allowing Black to play a in sente. When crawls further, can block because this is a tiger's mouth. So Black dies as explained in the L-group page.