This is a position from one of my games. I was white, and black resigned when I killed the group on the right and sealed it in. But a quick estimate of the score shows that if he can convert the lower right corner and the central moyo to territory, black can still win. It's not terribly uncommon to find positions like this in games at my level, and I'm curious what the proper follow up move for a reduction/invasion would be.

I'm assuming black's next move would be to strengthen the open right side of his moyo. After that, I might be able to win if I invade in the lower corner (I played out a quick sequence - it'd be close), but once I do that my opportunity for invasion/reduction in black's framework is close to nil. Is there a better place for me to attack first, or is the moyo too solid?

Click Here To Show Diagram Code

[go]$$B Black resigned - but should he have?
$$-------------------
$$|...................|
$$|.XXOO....X..XOOXXO.|
$$|X.XXO..OOXOX...XOO.|
$$|X..XO...X,XOOOOOXO.|
$$|.XXO.OOX..XOXXXOXXO|
$$|OXOOO......XXOOXO..|
$$|.OXO.........OXXO..|
$$|.XXO.........OOX...|
$$|.XO..OX......OXXX..|
$$|.XO,OX...X...OXOXXX|
$$|.OO.OX.......OXOOO.|
$$|..X.X.........OXO.O|
$$|..............OXXO.|
$$|..X..........O.XOO.|
$$|..............OOXX.|
$$|...X.....X....OXXO.|
$$|......X.....XXXOOO.|
$$|.............XOXO..|
$$|...............X...|
$$-------------------[/go]

Hi Jeromie, I didn't count (my counting is bad),
but if B still has a chance, my first feeling is LL corner.

What's your count for the current position ?

What do you mean ? The lower right corner is already W's.You mention the right side twice already —
but the right side is small. Because of W's massive thickness there,
B will not make anything big there. That's why the biggest area
is the LL corner.

I don't know how to roughly count, so I just approximate what the score would be if white gets everything he currently has and black gets everything he currently "has". I did not count the borders of territory nor did I count much for the top part of black's moyo. I just added 5 for it. Maybe it's not such a good eye to look at open areas and groups and give them values of 5 and 10, but I do it.

White 84.5
Black 103

is my estimate, ignoring captures. That's assuming white doesn't erase black's centre.

KGS score estimator (Though I had to add a few more black and white stones to the right before it counted those as dead, gives it as B+13.5 which is almost consistant with my counting.

If I counted right, white has about 100 points. Black has 20 points at the upper part and needs 80 points more in his moyo than white can achieve in the endgame. (Spot the monkey jump, the cutting point and erasing moves...) Mission impossible.

Cheers,
Vesa

Click Here To Show Diagram Code

[go]$$B
$$------------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X O O . . . . X . . X O O X X O . |
$$ | X . X X O . . O O X O X . . . X O O . |
$$ | X . . X O . . . X , X O O O O O X O . |
$$ | . X X O . O O X . . X O X X X O X X O |
$$ | O X O O O . . . . . . X X O O X O . . |
$$ | . O X O . . . . . . . . . O X X O . . |
$$ | . X X O . . . . . . . ? . O O X . . . |
$$ | . X O . . O X . . . ? ? . O X X X . . |
$$ | . X O , O X . . . X ? ? . O X O X X X |
$$ | . O O . O X . . . . ? ? . O X O O O . |
$$ | . . X . X . . . . . ? ? . . O X O . O |
$$ | . . . . . . . . . ? ? ? . . O X X O . |
$$ | . . X . . . . . . . ? ? . O . X O O . |
$$ | . . . . . . . . . . ? ? . . O O X X . |
$$ | . . . X . . . . . X . . . . O X X O . |
$$ | . . . . . . X . . . . . X X X O O O . |
$$ | . . . . . . . . . . . . . X O X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$------------------------------------------[/go]

White's right side is about 84 points of secure territory (including the captures). Black has about 14 points in upper left, a large moyo and some points in lower right (around the captured P2 stone). Thus, if w still gets komi, b has to get around 70 points with his moyo in order to keep up.

However white still has a monkey jump at a and nice reduction points at b and c. A white play at e threatens to break into the black formation via the cross-marked points and at the same time enables w to get some more points with his upper left group (about 10-15 pts seem realistic). There is also still the 3/3 invasion at f as last resort. I can not read if it still works here, but it may at least yield a ko.

All in all - it is very unlikely for black to keep up.

Click Here To Show Diagram Code

[go]$$B Black resigned - but should he have?
$$-------------------
$$|...................|
$$|.XXOO....X..XOOXXO.|
$$|X.XXO..OOXOX...XOO.|
$$|X..XO...X,XOOOOOXO.|
$$|.XXO.OOX..XOXXXOXXO|
$$|OXOOO......XXOOXO..|
$$|.OXO.........OXXO..|
$$|.XXO..e......OOX...|
$$|.XO..OX......OXXX..|
$$|.XO,OXM..X...OXOXXX|
$$|.OO.OX.......OXOOO.|
$$|..XMXM........OXO.O|
$$|.........c....OXXO.|
$$|a.X......b...O.XOO.|
$$|..............OOXX.|
$$|...X.....X....OXXO.|
$$|..f...X.....XXXOOO.|
$$|.............XOXO..|
$$|...............X...|
$$-------------------[/go]

(Edit: Typo)

Black's behind, but not by an insurmountable amount at the 9k level. Let's say black gets all of the area to the lower-left of the marked region (unlikely, but could happen especially at this level). Then I think the game is about even, and that's without black getting any points at all in the 'a' region. If white fails to invade the bottom left and also plays a passive endgame, I think black can still come back. The cut at 'b' makes it more difficult, but if white's playing passively white might not aim to exploit that.

Click Here To Show Diagram Code

[go]$$B
$$------------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X O O . . . . X . . X O O X X O . |
$$ | X . X X O . . O O X O X . . . X O O . |
$$ | X . . X O . . . X , X O O O O O X O . |
$$ | . X X O . O O X . . X O X X X O X X O |
$$ | O X O O O . . . . . b X X O O X O . . |
$$ | . O X O . . . . a . . . . O X X O . . |
$$ | . X X O . . . . . . . . . O O X . . . |
$$ | . X O . . O X . . . . . . O X X X . . |
$$ | . X O , O X . ? ? X . . . O X O X X X |
$$ | . O O . O X . . . ? . . . O X O O O . |
$$ | . . X . X . . . . ? . . . . O X O . O |
$$ | . . . . . . . . . ? . . . . O X X O . |
$$ | . . X . . . . . . ? . . . O . X O O . |
$$ | . . . . . . . . . ? . . . . O O X X . |
$$ | . . . X . . . . . X . . . . O X X O . |
$$ | . . . . . . X . . . ? ? X X X O O O . |
$$ | . . . . . . . . . . . . . X O X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$------------------------------------------[/go]

_________________
We don't know who we are; we don't know where we are.
Each of us woke up one moment and here we were in the darkness.
We're nameless things with no memory; no knowledge of what went before,
No understanding of what is now, no knowledge of what will be.

Hey, at least I counted right according to you! When you say including captures, are you considering the stones white may have captured and are now in his prisoner pile off the board? I'm not because I don't know what they may or may not be and say I counted without captures.

I mean, if I saw a turtle shell in an open board, would I count it as having 2 or 4 points worth of territory?

No, I meant the black stones, which are still on the board but which are obviously dead.

I would only count the 2 visible points, however for the final score, I would finally have to add the difference of already captured stones from the "piles". If I counted right, there are currently 70 black stones and 69 white stones on the board; thus if black resigned after the last white move, there must be one more white stone "in the pile" than black stones (except if black got handycap stones).

Thank you all for your comments. I've made a few replies below.

Probably the biggest thing I take from this conversation is the importance of being able to count in order to make cogent decisions about follow up play. I've gotten a lot better about making estimates while playing, but I rarely try to count the exact score. In a position like this, that can be important. This nicely reinforces on of Kageyama's fundamental lessons.

By the way, one thing I didn't mention: there were no handicap stones, but there was also no komi, so what does need to win the points on the board.


I meant the lower left corner... just a typo.



Yes, I was thinking that black would solidify his moyo before the corner, but that is probably the wrong order of moves.



Yes, this is the main point... white has solid territory and good thickness, but he can't play passively or he will still lose. I understand that white should win in this position, but I was curious about the right order of moves to make sure that large black area doesn't become territory.


Thanks for your comment. This is very much a game that I could still lose even if I should not. Very few positions are entirely safe for a 9 kyu! I'll probably go up a couple stones in strength when I can regularly win games where I am clearly ahead.


Thank you, schawipp for marking some of the key points! I saw a, b, c, and f, but I don't think I noticed how the move at e expands my territory and threatens the cut.