>> ERASURE

The following game illustrates a textbook case of an erasing move - a shoulder hit - being countered aggressively with an attempt to turn it into an invader.

Black was Kang Ch'eol-min 7-dan, whom some Koreans claim as the founder of the cosmic style of go. White was Seo Pong-su 9-dan. The game was in 1993.

White 34 was the classic erasure. But in this case, if Black answers it passively, he is in danger of losing by the equally classic fault of making a single large territory. Note that White has already created what is effectively an open skirt in the top right. Black therefore decided to counterattack on the outside with 37.

If you follow the rest of the game through, you will see some standard aspects of this concept. White tried to break out rather than go deeper. Black is happy to take massive outside influence. However, the critical point was Black 55, which was an overplay. When White poked out at 56, Black had to reinforce his outside wall with 57. That meant White was able to get to 64 first, which wiped out much of the value of Black's new wall - 64 could in fact be called an erasing move itself. Black was able to use his wall to attack strongly at 67 and 69, but he is now a step behind. After White 78, the right side has been rendered almost worthless and Black is behind already even on the board. He struggled on to move 276, however, before resigning, presumably in the hope that his thickness might bring some extra points in the endgame.

The full game in sgf form:

© John Fairbairn & T Mark Hall (GoGoD), London 2008.