11k vs 10k review request

Hi, I would really love if somebody could review a game I recently lost playing white (10k) against black (11k). White loses by resignation short after losing a giant game-deciding ko in the middle of the board.

I played seriously until the ko, which I did not anticipate and caught me completely by surprise. I thought a fight for connection would start after cutting, and I hoped to kill the invading stones into my huge mojo, but failed to see a ko forming. At that point I considered the game lost and so made some bad decisions in a sort of speculative despair before resigning. Specifically, one of my ko-threats was to kill a corner group, which my opponent correctly ignored eventually given the much much larger ko, and then I simply did not play the follow-up, believing that would not be enough, and trying desperately to kill a large group and similar moves, later resigning.

All in all, my belief is that I started very well in the fuseki, gaining huge influence towards the center and pushing the left invading group to a position where it would live very low, but then managed very poorly the reduction from the right, leading to the complete destruction of my mojo, and total solidification of black’s right territory.

Thank you very much for any helpful advise!

I am making a review on your game but I’ll finish it later tonight probably. Bit busy :slight_smile:

Okay here you go:

Hope it’ll be useful!

A couple things:

a) First of all, nice review. There’s a lot of good stuff in there, and it clearly took some time.

b) Secondly, move 6 is fine. It’s a reasonable move that reduces the value of black’s usual extension. In fact it’s been played over 100 times by the pros. (See ps.waltheri.net) But your explanation was so good I almost believed it myself.


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Thank you very very much for this review!

My feeling about the game was as described: I felt I started very well, due to the fact that I ended up with lots and lots of influence towards the middle, but lost the game when trying to cut black stones and the ko fight started.

Thanks to your review, I find that we both made important mistakes and that my big starting advantage stemmed in fact from a huge mistake of my opponent: With a different response on the key move 31, White’s situation changes from good to terribly bad.

Also, I find that the game-losing ko and mistakes stemmed original from the strategical mistake of trying to cut the black tones too severely, ignoring the very dangerous aji of the P14 stone. As pointed out, White should try to cut only the G12 black stones, securing very large amounts of territory in the process. I am still VERY bad at estimating the scores and territory during the game :frowning: I often find myself believing during the stone removal phase “Ok, I think the score is X” only to find I’m wrong by 50 points, which is obviously big enough to change the result.

On move 98 you write:

“There is nothing to be gained by sacrificing A. I don’t understand. It gives Black a really strong group and White still has to connect.”

Well, the explanation is actually very simple [Although the reasoning and strategy could be completely wrong]:

As stated before, I wanted to cut all of black stones with the sequence started at move 94. I even considered that letting those stones connect would now be game-losing. I was willing to start fighting for it, given white surrounding strenght. It is easy to read then that after M9 extends (as move 98) to save the stone, black ataris O11 and then white must respond N12, or else let black connect his stones, which we have already said is not the plan and we don’t want to and we consider would be game-losing. But then black O14 and then a net at M14 captures all of the white stones and the game would be over.

So that explains why 98 is played there. Given your comment, you clearly consider that black should capture M9 immediately instead of what was played, and white would then not be able to cut the inner black stones by playing O11 or similar, even though they would now be separated from the right side, because they have a lot of space.

Also, something I’ve not seen addressed but I would really like to know, as pointed out, is whether my score-estimation was justified or completely wrong, since my strategy was based on that very strongly, even choosing to resign, and choosing not to take the large corner black group, in a desperate try to kill the other even bigger group, since “I would lose anyway”.

To sum up these estimation-accuracy questions:

  1. Was I right to think I had a solid lead right after move 90, mainly due to my huge central mojo and solid lower side base?
  2. Was I right to think that after move 97, if black M11 stones lived, I would lose the game due to the mojo being mostly ruined with no hope to get enough compensation? (This is for example the reason I kept trying to cut them instead of letting them connect and settle for something else, justifying for example the “not undestandable” move 98)
  3. Was I right to think that, after black took the ko on move 117, simply capturing the black corner group, executing the threat, would leave me a losing position with not enough points (similar to 2)? [This belief is the reason I decided not to capture and instead go for the much more risky objective of killing the other larger black group, before resigning after failing to do so]
  4. Is there some advised way to practise global positional estimation? Things like “Black is 40 points ahead”. Even when only counting territories, as in the stone removal phase, I often find that my estimate can be like 50 stones off.

Lastly, thank you all very much once again, this review is very very very helpful!!

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First of all; Thank you for the detailed feedback! Nothing makes an annotator happier than seeing the person come back with more questions and details. Sometimes you’re not sure if the review was appreciated or not because people only tend to say thanks.

Secondly to mark5000: Yes you are right. It’s funny because the same night I was thinking that I spouted a lot of nonsense about that move being questionable. It makes Black’s extension rather slow and it strengthens the top a lot. I am far from strong enough to judge. I always try to add “perhaps”, “I am not sure” or “with a grain of salt” to things like this. If there is something I wanna avoid its to give people false information. Indeed, everyone should not take the annotators remarks with complete trust unless it’s a pro.

And back to you elsantodel:
I must admit that I made some errors in the later stage of the review (I got tired because it was getting late) such as the sacrifice at move 98 that you mentioned. I totally missed Black’s capturing sequence with O11 as you said (facepalm) and I see it caused you a lot of confusion. So sorry about that! It’s still true that you tried too hard to cut. There were some things I didn’t mention through the end since I rushed it a bit e.g that White could Q9 before Black encloses the right side (https://online-go.com/review/46916 at move 91 new variation).

To your question:

  1. After the sequence on the left Black got away with something she shouldn’t have and got some profit from it too. Also White lost opportunities to probe the shimari because Black became so solid. White had no corners neither and moyo was rather reduced. So Black had the advantage. Which takes me to the second question…
  2. Yes and No. Black had all corners BUT they were not holding too much territory. The amount that White could reduce Black while maintaining the moyo would be the key.So M11 is definitely a big focus since it reduces the moyo really well, making good use of the aji. In a sense your thinking was correct, it’s just that there were different ways to get back into the game other than cuting Black off which might be difficult to spot (see review I linked). If there was no way to reduce Black on the right then Yes, you would have to kill Black in the center.
  3. Yes, I think so. After Black won the KO she got a big moyo on the right and White had only low stones that could be pressed down for additional influence. You could indeed say that capturing the corner is too slow but it’s still so big that it’s hard to keep playing in sente through the game and then go back to capture it. But perhaps White didn’t have much choice.
  4. There are some good methods but I don’t really know them. Usually you can compare size of your areas with your opponents. If that doesn’t suit you, you could just count on your opponents time. I think it’s good to estimate atleast 3 times in your game before the endgame starts. You can decide your strategy from that. Learning to count just takes practice. The more you try the better you get at it.
    I am also horrible at counting, but I have a personal method of knowing wether I am ahead or not; In the game mistakes happends. E.g if my opponent plays something poor and I manage to get a better sequence (which I know must be better for me) then I have already made the estimation that I have an advantage. Then if I make a mistake I can compare how big that mistake was compared to the result I got when my opponent made one. From the opening to the middle game this usually adds up alot and I tend to plan my strategy there. It’s a rather abstract method though and might not be so reliable.