>> TRADES

It is surprisingly common, even among pros - as in this example - for a player who is ahead to assume that he will also come out ahead in any trade.

But trades can be unpredictable and, even if it can be true on financial markets, there is certainly no law in go that says the rich get richer. Here Hashimoto Shoji was the player who almost squandered his fortune.

After Black 99 he had established a comfortable lead - at least that was what he felt, which made him overconfident. He needlessly initiated a ko fight with 105 and 107, and by the time it was over, with 121, the game had become very close (Black got the centre right but gave up the upper left corner).

Among other comments on this game, you may consider it strange that the fuseki was said to end at move 25, but this is because the intent of White 26 was to fight. This is an aspect of the difference between the Oriental shi view of strategy as opposed to the Euro-American Clausewitzian approach. There are many such examples worth looking out for.

After the cut at 34, which made the game very complicated, both players spent a lot of time in thought. Having cut off two stones and forced Black 51, White won the first round of the middle game on points. It may have been this fact that led Hashimoto into accepting the later trade. Discarding a "spoiled" area may have seemed the dignified way for a pro to play.

Rin was guilty of slack play with 52. He should have invaded at 54. Another terminological nuance: at that point it would have been an invasion. After 53 it became an erasure. Hashimoto fought back aggressively with 67, 69 and 73 (a ladder breaker).

The reason Black got ahead was his skilful response to White's attack at 82, living with 83 and 85. Once the game became close, after the misguided trade, Rin went astray in the endgame under time pressure and so lost by 3.5 points.

The full game in sgf form:

© John Fairbairn & T Mark Hall (GoGoD), London 2007.