Lopsided game - who, why and how?

[Knotwilg]

$$c Position at move 71
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$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O . . X . . X . . . . X . . . . . |
$$ | . . . O . . . . . , . . . . . , X . . |
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$$ | . . . O . . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O . X . . |
$$ | . . . . . . . O O O . . . . . . X . . |
$$ | . . O . . O . X O X . . . . . O O X . |
$$ | . . . , . . O O X X . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . X . X O . . X . . . . . . O X X . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O X X X X . . . . . . . O O . . |
$$ | . . . X . . O O O . . . . . . O X . . |
$$ | . . O O X . . X O , . . . . . , X . . |
$$ | . . O X X O . . O . . O . X . X . . . |
$$ | . . O . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position at move 71
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$$ | . . . O . . . . . , . . . . . , X . . |
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$$ | . . . O . . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O . X . . |
$$ | . . . . . . . O O O . . . . . . X . . |
$$ | . . O . . O . X O X . . . . . O O X . |
$$ | . . . , . . O O X X . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . X . X O . . X . . . . . . O X X . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O X X X X . . . . . . . O O . . |
$$ | . . . X . . O O O . . . . . . O X . . |
$$ | . . O O X . . X O , . . . . . , X . . |
$$ | . . O X X O . . O . . O . X . X . . . |
$$ | . . O . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

In this game position, after Black 71, one of the two has a winning chance of 95%

1. Who is it? Why?
(question 2-4 are hidden)

White is winning.

2. What should be White's strategic objective?
3. Where's White's most obvious territorial gain?
4. Where's White major weakness? And how to deal with it?]

[Harleqin]

Kill! Lower left is not completely alive, so defend there, with a kosumi?

[jlt]

It reminds me of Bill's positional judgment problems. My guess was wrong, and I still don't understand the bot's evaluation.

Black has slightly less than 50 points and White slightly more than 40 points including komi, so Black is leading in terms of territory. Black's central group is not alive, but not so easy to kill. White has a weakness at B5. White's wall on the right is not alive yet, but looks stronger than Black's central group, so is not in danger. Where are White's points then??

[Knotwilg]

It reminds me of Bill's positional judgment problems. My guess was wrong, and I still don't understand the bot's evaluation.

If you try solving question 2-4 then you may get into the bot's evaluation. (I did )

And yes, the idea is to harvest positions from my games where one is clearly in the lead, like Bill's problems;

[Uberdude]

My analysis:

Can't tell who is winning from a glance, so need to count. First group statuses:
- White bottom left has a problem at b5, locally L group but then white gets ko to capture e4 stones, which isn't small, but less than corner so ko is a bit lighter for black
- black bottom left dragon isn't settled and bad shape at j7, but so big it's not going to die and emergency eye space around c10
- white bottom group reasonably settled in terms of eyes, thick shape towards centre
- black bottom right classic big safe corner
- white right wall thick but eyeless for now
- black right side safe (s8 looks premature)
- black upper right corner safe, but invasions possible
- black top left safe
- white top left safe
- white middle strong

So how about current territory, it's something like this. Top right isn't sure territory yet, but also l17 area could be another dozen with 1 black move and barely any if white first so transfer the ~6 expected there as generously saying corner is black. For bottom left white count as though black gets B7 sente kosumi to avoid counting ko variation. I'm counting g11 as alive, but actually with h16 f16 combo white can probably gobble it up for another dozen dame around e13 becoming territory, but then l17 more likely to become black too.

$$c Position at move 71
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$$ | . . . . M M M M . . . . . . . M M M M |
$$ | . . . X . M M M . . . . . . . M M M M |
$$ | M . O . . X . . X . . . . X . . M M M |
$$ | M M . O . . . . . , . . . . . , X M M |
$$ | M M M . . . . . . . . . . . . . . . . |
$$ | M M M O . . X . . . . . . . . . . M M |
$$ | M M . . . . . . . . . . . . O . X M M |
$$ | M M . . . . . O O O . . . . . . X M M |
$$ | . . O . . O . M O X . . . . . O O X M |
$$ | . . . , . . O O X X . . . . . O X X M |
$$ | . . . . . . . . . . . . . . . O O X M |
$$ | . . X . X O . . X . . . . . . O X X . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O X X X X . . . . . . . O O . . |
$$ | . M . X . . O O O . . . . . . O X . . |
$$ | M M O O X . . M O , . . . . . , X M M |
$$ | M M O X X O . . O . . O . X . X . M M |
$$ | M M O . X . . . M M M . . . . M M M M |
$$ | M M . . . . . . M M M . . . . M M M M |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position at move 71
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$$ | . . . . M M M M . . . . . . . M M M M |
$$ | . . . X . M M M . . . . . . . M M M M |
$$ | M . O . . X . . X . . . . X . . M M M |
$$ | M M . O . . . . . , . . . . . , X M M |
$$ | M M M . . . . . . . . . . . . . . . . |
$$ | M M M O . . X . . . . . . . . . . M M |
$$ | M M . . . . . . . . . . . . O . X M M |
$$ | M M . . . . . O O O . . . . . . X M M |
$$ | . . O . . O . M O X . . . . . O O X M |
$$ | . . . , . . O O X X . . . . . O X X M |
$$ | . . . . . . . . . . . . . . . O O X M |
$$ | . . X . X O . . X . . . . . . O X X . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O X X X X . . . . . . . O O . . |
$$ | . M . X . . O O O . . . . . . O X . . |
$$ | M M O O X . . M O , . . . . . , X M M |
$$ | M M O X X O . . O . . O . X . X . M M |
$$ | M M O . X . . . M M M . . . . M M M M |
$$ | M M . . . . . . M M M . . . . M M M M |
$$ ---------------------------------------[/go]

So black has:
- top left: 7
- top right: 13
- right: 9
- bottom right: 12
Total: 41

White has:
- top left: 13
- bottom left: 9
- bottom: 8
- middle: 2
- komi: 7
Total: 39

So only 2 difference in terms of points, but in terms of group strength I prefer white by more than 2 points, particularly as white has sente. So knowing one side the bot thinks is leading big I'll go for white, though I could well believe white was only leading a little.

Game plan should be to use thinness of black's group to:
1) ensure white lower group and right wall don't get bullied and worry about life
2) make some bonus points whilst attacking
3) ensure black doesn't make entire top side points, e.g. l/m17 and q17 are kinda miai now for white to reduce black points there, so keep those options open and if can build support for them from attack that's nice.

- j6 is an obvious shape point, but is it slack, can white even consider j7 cutting directly?
- l11/m11/m10 all turn head of black group whilst helping white wall, some potential to build some eyes and points around o10 area (would like to avoid black o11 peep)
- n5 is good topologically, but isn't building many points unless white can play in k7 area in sente first
- maybe white could just start operations at the top to try to take territory lead and leave sente moves against black middle in reserve until it's clear what direction is best, but I feel should press the group strength advantage as I worry after a black move at m11 black could be the one who bullies white.

[Bill Spight]

FWIW.

At first glance the game looks close to me. Black has a larger sphere of influence, but White is thick overall. I wouldn't have thought that one side or the other had a commanding lead. But Black seems to have the edge. Silly me! I forgot that Black has made an extra move. So, yeah, White has the move and the edge.

Upon closer examination I see that Black has played inefficiently in the bottom left and center. If I were playing the game as White, I would have noticed and probably figured that I was ahead.

My first thought was to invade the top. But just plonking down a stone at, say, M-17 is not very dynamic. Maybe P-17 for starters. Maybe O-18. It looks both ways, but it is perhaps too low?

My influence program is working again and so I fired it up. It estimates the board as even. It tends to overestimate thickness, So subtract 4 pts. from White. Then add komi and a few points for sente, and White is nicely ahead.

One thing the program does is show points where it gives one player at least 2:1 odds of controlling. It is unimpressed by Black's large group in the bottom left and center, giving it only 6 such points and no eyes. Large dragons never die, but maybe a good plan is to attack that group, keeping sente to invade the top. L-08 to take away the potential eye in the center and make some points with the White wall may be the way to go. It also leaves the Black group with only one 2:1 point. Thickness for attack!

[Knotwilg]

I've analyzed the position with LZ and the way I would interpret it largely corresponds to Uberdude's no-LZ analysis. Impressive!!!

Uberdude evaluates the ko in the lower left as lighter for Black but possible for White. According to LZ and per my interpretation, White will win this ko and Black won't have sufficient compensation for losing it.

For further analysis, see the sgf at 71:

[gennan]

According to KataGo, white is leading by 6-13 points from move 66 to move 71.

I'm sure that's lopsided for a superhuman AI (95%), but I dare say that a 10 point lead around move 70 is not a huge lead at lower dan level.

When I check the game with KataGo, the game was favourable for white since move 23. But just before the position of the original post, both players made a couple of 20 point mistakes in a span of 6 moves from move 61 to move 66. The frequency and size of those mistakes indicate that 10 points can evaporate quite easily at this level.

From move 61 to move 66, black missed a couple of opportunities to save his lower left group and white missed a couple of opportunities to kill it. White misses his last chance to kill on move 66 at F8.

This might be an interesting problem for players who haven't checked the game with an AI:

White to kill black in the lower left and take a 30 point lead.

$$c Position at move 66
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$$ | . . . O . . . . . , . . . . . , X . . |
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$$ | . . . O . . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O . X . . |
$$ | . . . . . . . O O . . . . . . . X . . |
$$ | . . O . . O . X O X . . . . . O O X . |
$$ | . . . , . . O O X X . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . . . . . . . X . . . . . . O X X . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O X X . X . . . . . . . O O . . |
$$ | . . . X . . O O O . . . . . . O X . . |
$$ | . . O O X . . X O , . . . . . , X . . |
$$ | . . O X X O . . O . . O . X . X . . . |
$$ | . . O . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position at move 66
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$$ | . . . O . . . . . , . . . . . , X . . |
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$$ | . . . O . . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O . X . . |
$$ | . . . . . . . O O . . . . . . . X . . |
$$ | . . O . . O . X O X . . . . . O O X . |
$$ | . . . , . . O O X X . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . . . . . . . X . . . . . . O X X . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O X X . X . . . . . . . O O . . |
$$ | . . . X . . O O O . . . . . . O X . . |
$$ | . . O O X . . X O , . . . . . , X . . |
$$ | . . O X X O . . O . . O . X . X . . . |
$$ | . . O . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

[Uberdude]

h7 looks tempting

[gennan]

Well spotted Uberdude!

[Knotwilg]

Well spotted Uberdude!

Funny: when you posted this position from my own game, which I had quite thoroughly analyzed before, with "white to kill", I also saw H7 immediately. Not to take anything away from Uberdude, who has given a very convincing display of his positional judgment and now his killer instinct. Nice!

Indeed, a 10 point advantage is not a sure path to victory at my level, as can be seen from almost any game of mine. But in this particular game I could really "feel" the advantage I had. I'm sensitive to a lead in thickness and I'm more frustrated when not capitalizing upon that then when losing a territorial lead.

I'll post a very different game next.

[Knotwilg]

$$c Position at move 49
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O O O . . X . . X . . O . . |
$$ | . . O , . . X . X , . . . . . X . O . |
$$ | . . O X . . . . . . . . . . . . X O . |
$$ | . . X X . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . X . . . . . . . . . . . X O . . |
$$ | . . O . . . . . . . . . . . X . O . . |
$$ | . . O X . X . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . X . O . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . O , X X . . . X . . . . . X O . . |
$$ | . . . O O X . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position at move 49
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O O O . . X . . X . . O . . |
$$ | . . O , . . X . X , . . . . . X . O . |
$$ | . . O X . . . . . . . . . . . . X O . |
$$ | . . X X . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . X . . . . . . . . . . . X O . . |
$$ | . . O . . . . . . . . . . . X . O . . |
$$ | . . O X . X . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . X . O . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . O , X X . . . X . . . . . X O . . |
$$ | . . . O O X . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

When we were children we used to play role games using the past tense "You were Cho Chikun and I was Takemiya".

Well, without saying which side I was, who do you think is 88% / 18pts ahead as per Kata's analysis after 14K plies?

It's White to play. Invade? Reduce? If so, where? What to expect?

[gennan]

Can you add coordinates please?

If I were white I would want to attach at L4. But the ladders are bad for white. So I would like to prepare for that with some probe/ladder block around O6, but I doubt if that's really possible.

So probably I wouldn't dare playing any deeper than L7.

I would feel behind with white, because I wouldn't feel very confident that I can reduce black's huge potential sufficiently. But perhaps an AI wouldn't have much of a problem with that.

[gennan]

Hmm. P7 appears to be a ladder block for the attachment at L4 and it may also give some more forcing moves later (like O8 or Q8?).

I think I want to change my answer to probing at P7. If black responds at Q7, white attaches at Q4. If black descends, white jumps to L6.

$$Wc Position at move 49
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O O O . . X . . X . . O . . |
$$ | . . O , . . X . X , . . . . . X . O . |
$$ | . . O X . . . . . . . . . . . . X O . |
$$ | . . X X . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . X . . . . . . . . . . . X O . . |
$$ | . . O . . . . . . . . . . . X . O . . |
$$ | . . O X . X . . . . . . . . 1 2 . . . |
$$ | . . O . . . . . . . 5 . . . . X . O . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . O , X X . . . X 3 . . . . X O . . |
$$ | . . . O O X . . . 4 . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Wc Position at move 49
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O O O . . X . . X . . O . . |
$$ | . . O , . . X . X , . . . . . X . O . |
$$ | . . O X . . . . . . . . . . . . X O . |
$$ | . . X X . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . X . . . . . . . . . . . X O . . |
$$ | . . O . . . . . . . . . . . X . O . . |
$$ | . . O X . X . . . . . . . . 1 2 . . . |
$$ | . . O . . . . . . . 5 . . . . X . O . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . O , X X . . . X 3 . . . . X O . . |
$$ | . . . O O X . . . 4 . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

It's still difficult for white, I feel.

If this is the continuation, I would see some light at the end of the tunnel for white, but definitely not an 18 point lead.

[Bill Spight]

Well, the bots have shown me that I don't know how to evaluate outside influence. But neither does Takemiya.

FWIW:

I'm going with Black, anyway. White has made two one space extensions from secure territory in both the bottom left and top left corners, and answered a peep, besides. That's inefficient. White also looks inefficient in the bottom right. As agains that, Black played a high approach in each of the corners on the left side, also inefficient. Also, Black extended to K-10 on the bottom side, which may or may not have been inefficient at the time. Now, however, White can easily invade the bottom side.

As White I would be hesitant to invade the bottom side, for fear that Black could take sente and secure a lot of territory in the center. I have won games by several dozens of points by doing just that.

So as White I think I would plonk down a stone where it would make the loudest sound: K-11. Call it invasion, call it reduction, I don't care.

What to expect? Chaos.

My influence program estimates Black as 43.5 pts. ahead on the board. Usually I subtract 4 pts. for its outside bias, but this position is ridiculous. Let's make it 10 pts. Subract 7.5 pts for komi, and 6 pts. for White having the move. That still leaves Black ahead by 20 pts.

BTW, for the next play it likes gennan's attachment at L-04.