Ouza Title Match (2)

What both players calculated during the endgame and postgame has been reported in detail on this site.

http://kifulog.shogi.or.jp/ouza/


It is said that △P*66 was losing move for gote at #102 because sente had the decisive attack at that moment.

The position at #101

At first, challenger Toyoshima had been thinking  △P*71 and △G-32 as candidate moves.
But, in the case of △P*71, after calculation with ▲G*53 △N*85 ▲+Rx92 △Lx ▲R-62 △K-23 ▲S*22 △P-25 ▲Px △+Bx ▲P*26 (Diag.1), he couldn't have any confidence in the position.

Diag.1

And, in the case of △G-32, it proceeds to quite complicated positions.
After calculation with ▲N-82+ △Sx68 ▲Gx △G*78 ▲Gx △Sx+ ▲Kx △B*69 ▲K-67 △B-58+ ▲K-66 △+B-46 (Diag.2) ▲S*31 △K-23 ▲N*15 △Px ▲G*22 △K-13 ▲S*14 △+Bx ▲Px15 (Diag.3), he was not sure which side was winning at Diag.3, and then finally evaluated the position as not good for gote. Thus, although he chose △P*66, as the result, △P*66 became a losing move. Habu considered the position as a very close game.

Diag.2

Diag.3

At Diag.2, △+B-46 is a threatmate with △+B58-57 ▲K-65 △+B57-56 ▲G*43. If the king run above like △K-75, the rook will be utilized by △Rx82.
The sequence from ▲S*31 to ▲Px15 is the technique for removing the threatmate and giving a threatmate to the opponent's king reversely. The other ways for gote to deal with the check would lead to a checkmate.
At first glance, you may think sente is winning at Diag.3. But, after this position, a lot of variations still exist. They are written in detail on the website. Please check it out.