Guzumi delayed too long => White's surprising wedge in the left centre
- Click Here To Show Diagram Code
[go]$$Bcm93
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . X . . . O X . |
$$ | . . . . . . . X O O . X O X O . . O . |
$$ | . . . . . X . O . . . X O . . O O . . |
$$ | . X O , . . . . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O . X O O X X O O . O X . . 2 . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . . . O X X O . X X X X . O O |
$$ | X O O X . X . O X O O X X O O O O . . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O . O . X X O |
$$ | X O O . O X . O X O . X X O O O X O O |
$$ | X O X O . X . O X O X . O X X X O O O |
$$ | O X X 1 X . . O X O O O O X O X O O X |
$$ | O . . . O X . O X X X X X . O X X O X |
$$ | O . X . . . X O O O O O O X O X . O X |
$$ | . X . . . . . O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
The old KataGo net was fine with delaying the guzumi even until after the Nakade Sequence at the left.
However, our investigation showed that -- after Black's final move
![black 93 :b93:](./images/smilies/b93.gif)
in the lower left -- White will occupy the guzumi point herself with
![white 94 :w94:](./images/smilies/w94.gif)
.
- Click Here To Show Diagram Code
[go]$$Bcm95
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . X . . . O X . |
$$ | . . . . . . b X O O . X O X O . . O . |
$$ | . . . . . X . O . . . X O a 2 O O . . |
$$ | . X O , . . . . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X 1 X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O . X O O X X O O . O X . . O . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . . . O X X O . X X X X . O O |
$$ | X O O X . X . O X O O X X O O O O . . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O . O . X X O |
$$ | X O O . O X . O X O . X X O O O X O O |
$$ | X O X O . X . O X O X . O X X X O O O |
$$ | O X X X X . . O X O O O O X O X O O X |
$$ | O . . . O X . O X X X X X . O X X O X |
$$ | O . X . . . X O O O O O O X O X . O X |
$$ | . X . . . . . O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
As usual with the "classical" line of play (i.e. without Black's guzumi), it is best for Black to play Michael Redmond's kikashi
![black 95 :b95:](./images/smilies/b95.gif)
in the bamboo joint just now.
White is forced to answer with the solid connection.
If she chose the atari at
a, instead, she would have lost a tempo in the Main Semeai, enabling Black to take the large endgame point of
b in the upper left corner, so winning the game.
- Click Here To Show Diagram Code
[go]$$Bcm97
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . X . . . O X . |
$$ | . . . . . . . X O O . X O X O . . O . |
$$ | . . . . . X . O . . . X O . O O O . . |
$$ | . X O , . . . . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X X X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O a X O O X X O O . O X . 2 O . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . . . O X X O . X X X X . O O |
$$ | X O O X . X . O X O O X X O O O O . . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O . O . X X O |
$$ | X O O 3 O X . O X O . X X O O O X O O |
$$ | X O X O 1 X . O X O X . O X X X O O O |
$$ | O X X X X . . O X O O O O X O X O O X |
$$ | O . . . O X . O X X X X X . O X X O X |
$$ | O . X . . . X O O O O O O X O X . O X |
$$ | . X . . . . . O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
Black will give atari at White's two stones in the lower left, in order to strenghten his position in the left centre.
White avoids some complications in the upper right (to be explained in some later posting) by defending there with
![white 98 :w98:](./images/smilies/w98.gif)
first.
Black
![black 99 :b99:](./images/smilies/b99.gif)
captures White's two stones.
Blocking at
a in the left centre, instead, will result in the same final score, as White will be able to connect her two stones later, or to gain alternatively in the forthcoming endgame on the left side of the board.
- Click Here To Show Diagram Code
[go]$$Wcm100
$$ +---------------------------------------+
$$ | . . . 8 5 . . . . . . . X . . . O X . |
$$ | . . . 6 2 1 7 X O O . X O X O . . O . |
$$ | . . . 4 3 X . O . . . X O . O O O . . |
$$ | . X O , . . . . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X X X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O . X O O X X O O . O X . O O . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . . . O X X O . X X X X . O O |
$$ | X O O X . X . O X O O X X O O O O . . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O . O . X X O |
$$ | X O O X . X . O X O . X X O O O X O O |
$$ | X O X . X X . O X O X . O X X X O O O |
$$ | O X X X X . . O X O O O O X O X O O X |
$$ | O . . . O X . O X X X X X . O X X O X |
$$ | O . X . . . X O O O O O O X O X . O X |
$$ | . X . . . . . O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
Black is still par with the Punishment Semeai Liberty Level, so White starts the endgame on the left side "early".
- Click Here To Show Diagram Code
[go]$$Wcm108
$$ +---------------------------------------+
$$ | . . . X O . . . . . a . X . . . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X . O . . . X O . O O O . . |
$$ | . X O , . . 6 . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X X X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O b X O O X X O O . O X . O O . |
$$ | O X . X c X . O O X O . . . X X X X X |
$$ | O X . X . 9 . O X X O . X X X X . O O |
$$ | X O O X . X . O X O O X X O O O O . . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O . O . X X O |
$$ | X O O X . X . O X O . X X O O O X O O |
$$ | X O X . X X . O X O X . O X X X O O O |
$$ | O X X X X 8 . O X O O O O X O X O O X |
$$ | O . . . O X 7 O X X X X X . O X X O X |
$$ | O . X . 2 1 X O O O O O O X O X . O X |
$$ | . X . . 4 3 5 O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
Black plays tenuki with
![black 13 :b13:](./images/smilies/b13.gif)
, in order to occupy the large endgame point at the top.
After
![black 15 :b15:](./images/smilies/b15.gif)
, we continued with the Main Semeai with White's peep at
a at the upper edge, finally scoring a White win by THREE points (komi = 1), which is one point better for her than the known solution to the problem.
KataGo's new net, howewer, found that Black's earlier mistake with not playing the guzumi should be punished even harder.
White will play the wedge at
![white 16 :w16:](./images/smilies/w16.gif)
in the left centre.
Playing KataGo's bad-shape move of
b just now would be a mistake.
Black already captured White's two stones in the lower left, so he is able to immediately block at
c without endangering his position in the left centre.
- Click Here To Show Diagram Code
[go]$$Bcm117
$$ +---------------------------------------+
$$ | . . . X O . . . . . . . X . . . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X . O . . . X O . O O O . . |
$$ | . X O , . . X . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X X X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O . X O O X X O O . O X . O O . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X 3 O 1 O X X O . X X X X . O O |
$$ | X O O X . X 2 O X O O X X O O O O . . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O . O . X X O |
$$ | X O O X . X . O X O . X X O O O X O O |
$$ | X O X . X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O . X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
Black must give atari from the outside.
- Click Here To Show Diagram Code
[go]$$Wcm120
$$ +---------------------------------------+
$$ | . . . X O . . . . . 5 6 X . . . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X . O . . . X O . O O O . . |
$$ | . X O , . . X . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X X X X O O . |
$$ | . X . O O O X X X O . . X . X O . . . |
$$ | O O O O 3 X O O X X O O . O X . O O . |
$$ | O X x X x X 1 O O X O . . . X X X X X |
$$ | O X x X X 2 X O X X O . X X X X . O O |
$$ | X O O X a X O O X O O X X O O O O . . |
$$ | X X O O X 4 . O X O . X O O O . X X X |
$$ | X X . O X b . O X O . X O O X X X O O |
$$ | X X O O X c d O X O . X O . O . X X O |
$$ | X O O X . X . O X O . X X O O O X O O |
$$ | X O X . X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O . X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]
![white 20 :w20:](./images/smilies/w20.gif)
is sente.
After Black connected at
![black 21 :b21:](./images/smilies/b21.gif)
, the time is ripe for KataGo's bad-shape move with
![white 22 :w22:](./images/smilies/w22.gif)
.
Black has to defend his cutting point at
![black 23 :b23:](./images/smilies/b23.gif)
-- sooner or later.
Please note that White's bad-shape move did not lose any tempo in the Main Semeai, but Black got only TWO points of territory in the left centre (one prisoner included), instead of the "usual" three.
If Black does without this defensive move, White would gain by the sequence of W
123, B
a, W
b, B
c, W
d in the left centre, once Black had occupied the
x liberties of her left-hand group in the Main Semeai.
As a result of White's newly found tesuji in the left centre, she will win the game by FOUR points now (komi = 1).