On combining the study of tsumego with the study of the endgame
Here, I think, is a good example. It is a modification of a problem from a Chinese book about semeai. (See
viewtopic.php?p=231227#p231227 )
- Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | . O X X O X X . X .
$$ | . . . X O O O X . .
$$ | . . O X . . . . . .
$$ +--------------------[/go]
The original problem is for Black to play and win the semeai, despite having only two dame to three. I have added a few stones on the outside to make it more well defined as a yose problem. (One defect of many yose problems is poor definition.)
- Click Here To Show Diagram Code
[go]$$Bc Black wins the semeai
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | C O X X W X X . X .
$$ | 4 1 3 X W W W X . .
$$ | 5 2 O X . . 7 C C .
$$ +--------------------[/go]
![white 6 :w6:](./images/smilies/w6.gif)
@ 2
![black 1 :b1:](./images/smilies/b1.gif)
is fairly obvious, making this in a way an easy problem. However, it is easy for the solver to miss
![white 2 :w2:](./images/smilies/w2.gif)
, which is White's best reply.
I don't know if this is the main line in the book, but it should be. Note that
![black 3 :b3:](./images/smilies/b3.gif)
at 7 also wins the semeai, but
![black 3 :b3:](./images/smilies/b3.gif)
is the better play. That fact should be taken into account, combining tsumego with yose.
In the region indicated by the marked points and stones, the local territory after
![black 7 :b7:](./images/smilies/b7.gif)
is Black +11.
Since we are now studying this as a yose problem, let's look at the play when White plays first. We'll return to the play when Black plays first later.
- Click Here To Show Diagram Code
[go]$$Wc White first
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | C O B B O X X . X .
$$ | C C 1 B O O O X . .
$$ | C C O B . . 2 . C .
$$ +-------------------[/go]
![white 1 :w1:](./images/smilies/w1.gif)
is the obvious play. Then after
![black 2 :b2:](./images/smilies/b2.gif)
the local territory is White +12.
OC,
![white 1 :w1:](./images/smilies/w1.gif)
is hardly a White sente, so let's look at the position after a White follow-up.
- Click Here To Show Diagram Code
[go]$$Wc White first, White follow-up
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | C O B B O X X . X .
$$ | C C O B O O O X . .
$$ | C C O B C C 3 5 6 .
$$ +-------------------[/go]
The descent,
![white 3 :w3:](./images/smilies/w3.gif)
, is best. Then later
![white 5 :w5:](./images/smilies/w5.gif)
is a 1 pt. sente.
The local territory is White +15.
And that means:
- Click Here To Show Diagram Code
[go]$$Wc White first
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | C O B B O X X . X .
$$ | C C 1 B O O O X . .
$$ | C C O B C C C C C .
$$ +-------------------[/go]
After
![white 1 :w1:](./images/smilies/w1.gif)
the territorial count in the marked region is White +13½.
This is a gote position. Each play gains 1½ pts.
Now let's go back and look at the play after Black plays first.
- Click Here To Show Diagram Code
[go]$$Bc Black first, Black follow-up
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | 4 O X X W X X . X .
$$ | 3 1 C X W W W X . .
$$ | C C W X C C 5 C C .
$$ +-------------------[/go]
![black 3 :b3:](./images/smilies/b3.gif)
makes territory in the corner.
![black 5 :b5:](./images/smilies/b5.gif)
could also make two eyes. The result is a local score of Black +17.
![black 3 :b3:](./images/smilies/b3.gif)
-
![black 5 :b5:](./images/smilies/b5.gif)
gains 6 pts.
Backing up:
- Click Here To Show Diagram Code
[go]$$Bc Black first
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | C O X X W X X . X .
$$ | C 1 C X W W W X . .
$$ | C C W X C C C C C .
$$ +-------------------[/go]
After
![black 1 :b1:](./images/smilies/b1.gif)
the territorial count is Black +11. This position is a White sente, following the main line above. The reverse sente gains 6 pts.
(No, I have not shown that it is a White sente. You are welcome to do so.
![Smile :)](./images/smilies/icon_e_smile.gif)
)
(BTW, you can tell that after
![black 1 :b1:](./images/smilies/b1.gif)
the local temperature has dropped because
![black 1 :b1:](./images/smilies/b1.gif)
prevents the atari at C-02 after White B-01.
![Smile :)](./images/smilies/icon_e_smile.gif)
)
- Click Here To Show Diagram Code
[go]$$Wc Original position
$$ | . . . . . . . . . .
$$ | . . O . . . . . . .
$$ | . . . O . . . . . .
$$ | . . . . X . X . . .
$$ | . O O O X . . . . ,
$$ | C O B B W X X . X .
$$ | C C C B W W W X . .
$$ | C C W B C C C C C .
$$ +-------------------[/go]
In the marked region the territorial count is White +1¼. This is a gote position. Each play gains 12¼ pts.