TesujiFromGames4/Solution

Problem diagram (black to play)  

In the problem diagram White has about 21 points of territory in the lower left. Black has a line of stones in the center of the lower half of the board. The crux of the problem is how to use the stones effectively? They can not be used to attack the three white stones to their right; those stones are already out into the center. They can not be used to attack the stones on in the lower left; those stones are strong.

Lee ChangHo's solution  

In this game, Lee ChangHo comes up with a novel move. Lee invades a secure corner! At the end of this sixteen move sequence, white still has about 21 points in the lower left (including the captured black stones), but black has landed four stones on the outside connected to his center left side group and facing his lower center line of stones. And black has sente!

However, an issue remains for black. How to deal with the two marked stones in the upper left. These stones open the lower center left area that black is creating. They must be sealed of from that area or captured. See Tesuji From Games 5.

The game is Lee ChangHo (black) versus Park YoungHoon in the 9th LG Cup played on 14 October 2004.