by James Sedgwick 6D
Thursday morning’s game provided a spectacular finish to the last semi-final round, as Bill Lin and Guanyu Song faced off for a seat in the final. Guanyu Song, playing black, chose a very center-oriented play in the early going, increasing his central power with the triangled moves. Then when a fight started at the top Bill (white) made a judgement to skip the normally mandatory move at A, granting a huge swing in the corner in return for a strong center position with the shown game move (J13 in dia 1, left). While this favors black quite a lot locally, the value of the center was so large here it made sense, and Bill started holding a small lead.
The fighting continued for a while, with Guanyu looking for a chance for a reversal. Finally he found a brilliant strike (T8 in diagram 2, right). If Bill responds passively, the game will swing back to a balanced position, but if he resists, the whole side not only turns into a ko, it’s one that white cannot finish with a single move. It seemed like Bill had no good choices, but he proceeded put on a clinic in managing a ko like this. First, he left the ko in flux, while he continued to build thickness through the whole board. Eventually he started the ko, and although Guanyu captured the whole right side, his thin positions elsewhere enabled Bill to collect enough profit to close out the game.