Macelee's study journal of interesting pro games: 2013-09-09
Murakawa Daisuke 7-dan is having a good year. He has won 4 games in a row in one of the two leagues in the prestigious Kisei tournament. This put him in an enviable position of being just one game away from challenging the Kisei title. Today I am studying one of his Kisei league games against Kono Rin 9-dan.
Opening so far is peaceful. is a common way to reduce such corner. Sequence to may be called a joseki. For readers not familiar with this shape, professionals rarely make the 'a'/'b' exchange, although 'a' is clearly a sente move. The exchange would make the white corner very solid and unconditionally alive, exposing black's own weakness (aji at 'c').
On the other hand, if black's outside is strong enough, black can attack at 'b' directly, which can lead to an approach ko (for details, see http://www.go4go.net/go/carpenter_square_16). Let's see how Murakawa handle this situation.
[go]$$Wm44 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . c 6 3 5 . b . | $$ | . . . O . . . . . X . . . . 2 1 . . . | $$ | . . O , . . . . . , . . . . 4 X 7 9 . | $$ | . . O X . . . . . . . . . . . . 8 a . | $$ | . . X O O . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X . . . . . . . . . . . . . . . | $$ | . . O X . . . . . . . O X X X . . . . | $$ | . . O O O O . . . , O X O X . X X . . | $$ | . . . O X X . X . . . . O O X . . . . | $$ | . . . . O X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]
Now black's outside looks not strong enough, but entered the corner any way! What is the logic behind this move? naturally strengthen the wall, adding more pressure to the marked group. is a must, otherwise, black 'a', white 'b', black , white 'c', black 'd' - white cannot capture these black stones. Next, continued adding pressure to white's side group. had to be really careful because black is trick everywhere.
[go]$$Bm53 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . c . | $$ | . . . . . . . . . . . . . X O O b 1 d | $$ | . . . O . . . . . X . . . . X O a 4 . | $$ | . . O , . . . . . , . . . . X X O O . | $$ | . . O X . . . . . . . . . . . . X 2 . | $$ | . . X O O . . . . . . . . . . 3 . . . | $$ | . . X . . . . . . . . . . 7 . . X . . | $$ | . . . . . . . . . . . . . . . 6 . . . | $$ | . . . . . . . . . . . . . . 5 . @ . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . @ . . | $$ | . . . . . . . . . . . . . . . . . 8 . | $$ | . . X X . . . . . . . . . . . . . . . | $$ | . . O X . . . . . . . O X X X . . . . | $$ | . . O O O O . . . , O X O X . X X . . | $$ | . . . O X X . X . . . . O O X . . . . | $$ | . . . . O X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]
The next move really surprised me. Can you guess it? (I will hide the rest of this post)
black at first sight is really slow. Even if white ignore, black can only create a ko in the corner following the sequence of black 'a', white 'b', black 'c', white 'd', black 'e', white 'f', black 'g'. Please verify this is an approach ko - meaning that black would have to spend three moves in total to kill this corner, not necessarily a wise thing to do.
[go]$$Bm61 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . g f e . c . | $$ | . . . . . . . . . . . . . X O O a X b | $$ | . . . O . . . . . X . . . . X O d O . | $$ | . . O , . . . . . , . . . . X X O O . | $$ | . . O X . . . . . . . . . . . . X O . | $$ | . . X O O . . . . . . . . . . X . 1 . | $$ | . . X . . . . . . . . . . X . . X . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . . . . . . . . . . . . X . O . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . O . | $$ | . . X X . . . . . . . . . . . . . . . | $$ | . . O X . . . . . . . O X X X . . . . | $$ | . . O O O O . . . , O X O X . X X . . | $$ | . . . O X X . X . . . . O O X . . . . | $$ | . . . . O X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]
However, Murakawa had a better plan! It is not easy to find (move 105) because white has already defended at . However, Murakawa played this any way. After forcing moves and , revealed black's plan - now 'a' and 'b' are miai points. Note that 'b' would create a direct ko, a lot better than the approach ko in the previous diagram.
Murakawa smartly exploited the weakness of two white groups. Kono did not know what to do so he played tenuki. He lost the game quickly.
[go]$$Bm105 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . X . . . . . | $$ | . . . . . . . . . . . X O X O O 6 X 5 | $$ | . . . O . . X X X X . . X O X O . O 3 | $$ | . . O , . O O O O X . . . O X X O O 4 | $$ | . . O X . . . . . O X . . . O X X O b | $$ | . . X O O . . . . O X . . . . X . X . | $$ | . X X . . . . . . . . . . X . . X . 7 | $$ | . O X X O . . . . O . . . . . O . . . | $$ | O . O X O . . . . . . . . . X . O 2 a | $$ | . O X O . . . . . , . . . . . , . 1 . | $$ | . X X O . O . . . . . . . . . . . . . | $$ | . X O X X . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . @ . | $$ | . . X X . . . . . . . . . . . . . . . | $$ | . . O X . . . . . . . O X X X . . . . | $$ | . . O O O O . . . , O X O X . X X . . | $$ | . . . O X X . X . . . . O O X . . . . | $$ | . . . . O X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]
Author:
logan [ Mon Sep 09, 2013 3:17 pm ]
Post subject:
Re: Macelee's study journal of interesting pro games: 2013-0
You may also remember this shape from one of our esteemed 1-on-1 Malkovich games, Yithril vs. Magicwand mv. 25, which generated a fair amount of discussion from the spectators.
Author:
TheBigH [ Mon Sep 09, 2013 9:13 pm ]
Post subject:
Re: Macelee's study journal of interesting pro games: 2013-0
is a common way to reduce such corner. Sequence to 
may be called a joseki. For readers not familiar with this shape, professionals rarely make the 'a'/'b' exchange, although 'a' is clearly a sente move. The exchange would make the white corner very solid and unconditionally alive, exposing black's own weakness (aji at 'c'). 
entered the corner any way! What is the logic behind this move? 
naturally strengthen the wall, adding more pressure to the marked group. 
is a must, otherwise, black 'a', white 'b', black 
continued adding pressure to white's side group. 
had to be really careful because black is trick everywhere.
at first sight is really slow. Even if white ignore, black can only create a ko in the corner following the sequence of black 'a', white 'b', black 'c', white 'd', black 'e', white 'f', black 'g'. Please verify this is an approach ko - meaning that black would have to spend three moves in total to kill this corner, not necessarily a wise thing to do.
(move 105) because white has already defended at 
. However, Murakawa played this any way. After forcing moves 
and 
, 
revealed black's plan - now 'a' and 'b' are miai points. Note that 'b' would create a direct ko, a lot better than the approach ko in the previous diagram.