Life In 19x19

Honinbo game 5 2nd day is underway. Yamashita is 1-3 down so needs to win to avoid defeat. Following along with Elf it thinks he was doing pretty well until around move 112 where it thinks he made several big mistakes and Iyama now leading. My guess is it won't swing back to Yamashita, Iyama seems to be much better at holding on to a lead once he gets it. There is a funny semeai thing on the board though that I think is probably some long ko so maybe Elf isn't evaluating correctly, but playing around with the position there are no jumps in winrate when I clarify it so it's probably fine with it.

From the opening, Elf says Iyama's biggest mistake was an interesting 'big picture' idea. Iyama played 28 as the undermining approach to the big shimari, Yamahishita pincered, and Iyama the now normal attachment in the corner to make a group here and they played this modern joseki.

Click Here To Show Diagram Code

[go]$$Wcm28 Iyama (white) vs Yamashita
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X O O X . . X . . . . O X X . . . |
$$ | . . . O . X . . . , . . O . O , X . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . O . . . . . . . . . O . . . . . |
$$ | . . . . . O . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 7 . . . |
$$ | . . . O . . . . . , . . 0 X 6 3 X . . |
$$ | . . . . . X . . . 2 . 1 . 9 5 4 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

However, Elf strongly thinks white should not have continued in the corner, but cap at the top (12% better). This looks like a nice large scale topography type move, loosely linking up the top left and top right white groups whilst pressuring black on top. It also helps deal with weakness of the f13 knight move. The m3 k3 exchange is pretty neutral according to Elf, but continuing locally is quite natural (m5 jump better than attachment though apparently).

Click Here To Show Diagram Code

[go]$$Wcm30 Elf's move
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X O O X . . X . . . . O X X . . . |
$$ | . . . O . X . . . , . . O . O , X . . |
$$ | . . . . . . . . 1 . . . O X . . . . . |
$$ | . . . O . . . . . . . . . O . . . . . |
$$ | . . . . . O . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . X . , X . . |
$$ | . . . . . X . . . X . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

If black says "Hey, I'm going to make that a bad exchange" and reinforces the corner (-7%), white could just continue solidly on top at g15. Better for black would be r13, c8 and m17 being distant 2nd/3rd choices. Black r13 being the right answer gives the hint that white g15 is actually soft, best would be r14, black answers at q9 and then white plays g15. Elf also thinks white should have capped instead of m3, but only a minor mistake.

Click Here To Show Diagram Code

[go]$$Wcm30 Elf's move
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X O O X . . X . . . . O X X . . . |
$$ | . . . O . X . . . , . . O . O , X . . |
$$ | . . . . . . 3 . 1 . . . O X . . . . . |
$$ | . . . O . . . . . . . . . O . . . . . |
$$ | . . . . . O . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . X . , X . . |
$$ | . . . . . X . . . X . O . 2 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

Edit: poor Yamashita:

Iyama did indeed win, so retains the Honinbo title for the 7th year in a row.

Thanks for the detailed analysis, Uberdude!
Shame that Yamashito could not make it better than a 1-4 defeat. It seems that he had quite a few chances but had a harder time during the second half of the games. In other words, inmany games it looked like Yamashita got a good/better position out of the opening/beginning of the middle-game. Is it because opening is a known weak (relatively speaking) point of Iyama or because Yamashita's opening is acknowledged as his forte?

Shenoute wrote:Thanks for the detailed analysis, Uberdude!
Shame that Yamashito could not make it better than a 1-4 defeat. It seems that he had quite a few chances but had a harder time during the second half of the games. In other words, inmany games it looked like Yamashita got a good/better position out of the opening/beginning of the middle-game. Is it because opening is a known weak (relatively speaking) point of Iyama or because Yamashita's opening is acknowledged as his forte?

I get the impression Iyama is experimenting with new opening ideas from bots, so being less familiar with them can end up going behind in the opening (by the judgement of such bots, I don't know if Yamashita would have felt the same in the game). Once you get to fighting in late middlegame the effect of those less familiar opening shapes has diminished so his greater strength shines though. I also think Yamashita's play deteriorates more when he has to play quickly.