Macelee's study journal of interesting pro games: 2014-07-20

macelee · #1

This is a position from a Japanese Kisei League game a few days ago:

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . O . X . . | $$ | . O . O O . O . . . . . . . . O X . . | $$ | . X X O X X O . . O O O . . O X . . . | $$ | . O O X . X . O X O X X O . O , X . . | $$ | . . O X X X . X . X . . . O . . . . . | $$ | . O X O O O X X . X X X X O . X . . . | $$ | . O X X O O O . X . O X O O . . . . . | $$ | 1 O X . X O . . O O O O X X . X . . . | $$ | . X X X . O . O O X . . X . . . . . . | $$ | X O O O O O X . . X . O X . . , . . . | $$ | X O X X . O X . O . . O X . . . X . . | $$ | . X . O O O X . . . . O X . . O X . . | $$ | X . X X O X X O O . . . X . O X X O . | $$ | . X X X X X X X . . O O . . O . O . . | $$ | . X . O . O . . . X . X . X O . . O . | $$ | . O O , . O O . . , . O O X X , O . . | $$ | . . . O X O X . O . . . . O X X X X . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

is a such as big reverse yose! White would have got this position in sente, securing 15 points in the corner as shown below:

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------------------+ $$ | M M M . . . . . . . . . . . O . X . . | $$ | M O M O O . O . . . . . . . . O X . . | $$ | M Z Z O X X O . . O O O . . O X . . . | $$ | M O O X . X . O X O X X O . O , X . . | $$ | M M O X X X . X . X . . . O . . . . . | $$ | M O X O O O X X . X X X X O . X . . . | $$ | M O X X O O O . X . O X O O . . . . . | $$ | O O X . X O . . O O O O X X . X . . . | $$ | X X X X . O . O O X . . X . . . . . . | $$ | X O O O O O X . . X . O X . . , . . . | $$ | X O X X . O X . O . . O X . . . X . . | $$ | . X . O O O X . . . . O X . . O X . . | $$ | X . X X O X X O O . . . X . O X X O . | $$ | . X X X X X X X . . O O . . O . O . . | $$ | . X . O . O . . . X . X . X O . . O . | $$ | . O O , . O O . . , . O O X X , O . . | $$ | . . . O X O X . O . . . . O X X X X . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

After the reverse yose, the corner has only 8 points left, due to the following tesuji:

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------------------+ $$ | M M M . . . . . . . . . . . O . X . . | $$ | M O 6 O O . O . . . . . . . . O X . . | $$ | 4 Z Z O X X O . . O O O . . O X . . . | $$ | . O O X . X . O X O X X O . O , X . . | $$ | 1 2 O X X X . X . X . . . O . . . . . | $$ | 5 O X O O O X X . X X X X O . X . . . | $$ | 3 O X X O O O . X . O X O O . . . . . | $$ | X O X . X O . . O O O O X X . X . . . | $$ | . X X X . O . O O X . . X . . . . . . | $$ | X O O O O O X . . X . O X . . , . . . | $$ | X O X X . O X . O . . O X . . . X . . | $$ | . X . O O O X . . . . O X . . O X . . | $$ | X . X X O X X O O . . . X . O X X O . | $$ | . X X X X X X X . . O O . . O . O . . | $$ | . X . O . O . . . X . X . X O . . O . | $$ | . O O , . O O . . , . O O X X , O . . | $$ | . . . O X O X . O . . . . O X X X X . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

So let's have a positional judgement. White has about 27 points at top side :

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------------------+ $$ | M M M M M . M M M M M M M M O . X . . | $$ | M O . O O . O M . M M M M M . O X . . | $$ | . Z Z O X X O . . O O O M M O X . . . | $$ | . O O X . X . O X O X X O M O , X . . | $$ | . . O X X X . X . X . . . O . . . . . | $$ | . O X O O O X X . X X X X O . X . . . | $$ | . O X X O O O . X . O X O O . . . . . | $$ | 1 O X . X O . . O O O O X X . X . . . | $$ | . X X X . O . O O X . . X . . . . . . | $$ | X O O O O O X . . X . O X . . , . . . | $$ | X O X X . O X . O . . O X . . . X . . | $$ | . X . O O O X . . . . O X . . O X . . | $$ | X . X X O X X O O . . . X . O X X O . | $$ | . X X X X X X X . . O O . . O . O . . | $$ | . X . O . O . . . X . X . X O . . O . | $$ | . O O , . O O . . , . O O X X , O . . | $$ | . . . O X O X . O . . . . O X X X X . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

White has about 27 points at bottom side:

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . O . X . . | $$ | . O . O O . O . . . . . . . . O X . . | $$ | . X X O X X O . . O O O . . O X . . . | $$ | . O O X . X . O X O X X O . O , X . . | $$ | . . O X X X . X . X . . . O . . . . . | $$ | . O X O O O X X . X X X X O . X . . . | $$ | . O X X O O O . X . O X O O . . . . . | $$ | 1 O X . X O . . O O O O X X . X . . . | $$ | . X X X . O . O O X . . X . . . . . . | $$ | X O O O O O X . . X . O X . . , . . . | $$ | X O X X . O X . O . . O X . . . X . . | $$ | . X . O O O X . . . . O X . . O X . . | $$ | X . X X O X X O O . . . X . O X X O . | $$ | . X X X X X X X . . O O . . O . O . . | $$ | . X . O . O . . . X . X . X O . . O . | $$ | . O O , . O O . . , . O O X X , O . . | $$ | . . M O Z O Z . O . . M . O X X X X . | $$ | M M M M M M M M M M M . . O X . . . . | $$ | M M M M M M M M M M M . . . . . . . . | $$ +---------------------------------------+[/go]

White has about 11.5 points in the middle. Note that white in the future has the option to capture the two :bs:

stones, gaining 5 points. So for counting now, I add half of the value - 2.5 points to white's total.

Click Here To Show Diagram Code: [go]$$B $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . O . X . . | $$ | . O . O O . O . . . . . . . . O X . . | $$ | . X X O X X O . . O O O . . O X . . . | $$ | . O O X . X . O X O X X O . O , X . . | $$ | . . O X X X . X . X . . . O . . . . . | $$ | . O X O O O X X . X X X X O . X . . . | $$ | . O X X O O O . X . O X O O . . . . . | $$ | 1 O X . X O . . O O O O X X . X . . . | $$ | . X X X . O . O O Z . . X . . . . . . | $$ | X O O O O O X . . Z M O X . . , . . . | $$ | X O # # . O X . O M M O X . . . X . . | $$ | . X . O O O X . . M M O X . . O X . . | $$ | X . X X O X X O O . . . X . O X X O . | $$ | . X X X X X X X . . O O . . O . O . . | $$ | . X . O . O . . . X . X . X O . . O . | $$ | . O O , . O O . . , . O O X X , O . . | $$ | . . . O X O X . O . . . . O X X X X . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

So white has a total of 27+27+11.5+6.5(komi) = 72 points

Black has about 3 point in the left group, 2 in the central group. The right side appears to be very large - about 75 points. Because it's white's turn to play, so the game is still quite close. However, what happened next surprised me a lot. White managed to exploit ajis in black territory to create a big ko! Please view the full game at http://www.go4go.net/go/games/sgfview/42690

This is how the game looks like in the end:

Click Here To Show Diagram Code: [go]$$W $$ +---------------------------------------+ $$ | . . . . . X O O . . . . . . O . X . . | $$ | . O . O O X O . O . . . O O . O X . . | $$ | . X X O X X O O X O O O . . O X . . . | $$ | . O O X . X O O X O X X O O O X X X . | $$ | . . O X X X X X X X X O O O X X O X O | $$ | . O X O O O X X . X X X X O O X O . X | $$ | . O X X O O O O X X O X O O X X X O . | $$ | X O X O . O . . O O O O X X X X O X O | $$ | X X X X O O . O O X . X X X X X O . O | $$ | X O O O O O X . X X . O X O O O O O O | $$ | X O X X . O X X O X . O X X X X X O O | $$ | . X . O O O X . . O O O X X X . X X O | $$ | X . X X O X X O O . . X X O O X X O O | $$ | . X X X X X X X . . O O O . O O O O O | $$ | X X . O . O . . O X . X O . O . . O . | $$ | . O O , . O O . . , . O O . . , O O . | $$ | . . . O X O X . O . . . . O . . . . . | $$ | . . . . . . . . . . . . O O . . . O O | $$ | . . . . . . . . . . . . O . O . . . O | $$ +---------------------------------------+[/go]

emeraldemon · #2

Very interesting, thanks!

handa711 · #3

Thanks for the analysis, but why couldn't you post the game here instead of linking to go4go.net?

Vesa · #4

Takao Shinji Judan might have thought that the costly mistakes were made earlier:

http://blog.goo.ne.jp/s-takao-san/e/d5fbd3e38bf43ccc920a9aacc92c897b

Cheers,
Vesa

John Fairbairn · #5

Quote:

Takao Shinji Judan might have thought that the costly mistakes were made earlier:

http://blog.goo.ne.jp/s-takao-san/e/d5f ... acc92c897b

Indeed. But ... He said he erred on Black 53. He felt slightly uncomfortable at this point but chose this move anyway, when what he ought to have done was to protect his eye shape at once with J16. Because he didn't, he fell into a vicious circle where things got gradually worse. He either overlooked or misjudged White's probe 54.

The "but..." is because he managed to reverse fortunes later on and ought to have won, and another "but" is that under time pressure he made mistakes in the endgame which then lost him the game. Not a nice way to lose, he said, but added he had no-one to blame but himself.

Unfortunately he doesn't say what the mistakes were. Presumably there was at least one in the area highlighted by macelee, but the ko-burdened capturing race in the lower right may well have featured another one.

oren · #6

Well, he does say he was able to come back from an earlier mistake but lost again later in byoyomi.

Macelee's study journal of interesting pro games: 2014-07-20

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