The Mystery of 19×19

(continued from part 3)

White 100 is the strongest counter move to black 99. However, after
B 101 and 103, white has to find a way to escape the middle group or he
would resign. Aiming at both A and B, white played 108, a move that was
overlooked by black and all pro observers.

Black chose to defend his own weakness at 109, and white played at
112, another very nice tesuji. Now if black continues to play at the
center, it would become a ko, and white would be able to utilize his
ko-threats from the dead group.

After deciding he could not afford a ko, black chose to separate
white’s right side as an exchange for his three stones in the middle.
However, such exchange shifted the balance of the game, and the
position is already slightly favorable for white now.

The yose continues on. White’s 144 and Black’s 149 are both
somewhat careless. Finally, white played at 150, aiming at black’s
whole group and the cutting point at A.

After W played at 166 (at 154), black must play at A to make two eyes for his group.  Therefore, white would get B, which threats black’s 5 stones and aiming at D.

After another 50 yose moves, the most exciting moment arrived.
White is winning the game by 1 point with komi, but he deliberately played at 248. Black’s 249 put white’s 15 stones under attari, but his own group is short of liberties too…

Wow, Black captured 15 stones in the center, but white managed to live his dead group. That’s a huge exchange at the very end of the game, but white still gained.

White wins by 11 points.