From another thread the issue of the effect of an opening advantage on who wins the game came up. User 'often' was of the view that it had no effect on win rate, whereas I thought it had a small advantage, my guesstimate was a 10 point lead for KGS 5ks would lead to a perhaps 55-60% win rate, and maybe 65% for KGS 3ds. This thread is to test that by picking games from KGS or elsewhere, making a judgement of the position after the opening (and interesting exercise in itself) and then seeing who wins.

So to kick things of I picked a random KGS 3d game:

And this game is near enough to even after the opening and once the middlegame fighting starts that it can't contribute to this experiment.

Next game! (I suspect most games will be within 10 points after the opening so hunting for suitable games will take a while; maybe we should use weaker players).


Again even after opening.

Table of results so far:

Might be interesting to have a strong engine evaluate (yeah not ideal) the opening (when does it know the opening is finished?) so that games can be done in batch? See what correlation there is between evaluation function and result?

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12k: 2015.08.11; 11k: 2015.09.13; 10k: 2015.09.27; 9k: 2015.10.10; 8k: 2015.11.08; 7k: 2016.07.10 6k: 2016.07.24 5k: 2018.05.14 4k: 2018.09.03 3k: who knows?

Yup, I suggested that on the original thread, this is the manual version. Anyone have crazystone/fuego/pachi/zen etc and fancies writing a script?

How about my game? Who was ahead in the opening?

I don't think many people (if any) can accurately estimate the score after the opening and the beginning of the middle game. If pros could do this we'd see many games resigned after the opening. Another point is that there is no clear way to specify when the opening ends. Middlegame fights happen during the opening sometimes. And what about those games with no fuseki? Of course fuseki is not synonymous with opening.

I think there's a difference between estimating the score, and knowing the result. I'm sure there are board positions where pros would unanimously agree that one side, black or white, is ahead. But it doesn't mean that it's the end of the game - pros make mistakes, too.

In one of the other study journals, someone recently brought up an old game from 2010 where Lee Sedol died pretty big early in the game. He happened to go on and win it.

Around that time, Myungwan was giving a workshop in the bay area, which I attended. I remembered him commenting about that game. He said he took a look in the early middle game, and it looked like Lee Sedol had lost, so he stopped watching, and went on to do something else. When he came back to see that Lee Sedol had won, he was surprised.

I doubt that Myungwan's estimation that Lee Sedol was behind after dying was inaccurate. Probably Lee's chances of winning were pretty slim. Comebacks can still happen, though, which is why I think there's a difference between estimating the score and knowing the result.

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I should have said I doubt many people can predict who will win after the opening, rather than estimate the score. My comment about seeing resignations after the opening still applies.

Uberdude how are you picking where the opening ends?

gowan you don't think we can say it's more likely for one player to win the game when he has an opening advantage? Uberdude's examples talked about 55% or 65% chance to win. I don't see how you jumped from that to the disadvangated player should resign?

Then, I agree with you.

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OK, I will bite. If we call the first 18 moves the opening, I would say W was slightly ahead, mostly because the exchange in the lower right corner was good for W. But the difference is not enough to significantly affect the result at any amateur level. Maybe 52% chance for W to win?

I am not strong enough to say much about the middle game fighting through move 45. However, I am reasonably confident that both sides made mistakes which were large enough to overcome any small opening advantage or disadvantage

The invasion at move 47 looks likely to get B into deep trouble. I think I would have looked for a lighter way of reducing, maybe at Q11. Or possibly a deep invasion with more aji like S15, making miai of R17 and R12. The bad result B got here certainly affected the game outcome more than all previous moves combined. After W60, I would bet 80% on W winning. By W76, that goes to 90%.

Game 1
nomatter v. thechaboot
at the point of white 26 it's a relatively simple opening with b having a smaller advantage, but black chose a fight and white made his group heavy. because of that decision the opening is over and it's a middle game battle.

Game 2
nomatter v. thechaboot
Opening is pretty much done after move 19. Seems even with it leaning a little towards white because of his moyo. However, white chooses to invade and jumps into a middle game situation afterwards with a running group.


Game 3
greendemon v. kykkk
the middle game started around move 46, at that point white had the advantage but there was a way for B to live with his invasion that could've changed the board situation.


The fact that people are handpicking these exposes this to some sort of bias

Perhaps you should also provide insight as to when you think the opening/middle game transition happens and what the standing is.

Please don't get hung up on the precise meaning of 10 points. +/-50% is fine. "A bit but not a lot" is the meaning. Or "a bit more than komi".

My game selection algorithm was:
1. try to remember the KGS 3d I played a few days ago.
2. look in his game history for the first even game against a 3d

I don't see that adding much bias. That both games were within ten points after the opening was as I expected.

My rule of thumb for the end of the opening is around move 50. In this case, I would say move 46. (The fuseki ended, as mitsun indicates, at move 18.)

I think that White is clearly ahead, as Black has made two small groups on the top side, and the one on the left is plainly insecure, and the one on the right has too many stones. White's group is also insecure, so maybe White should have continued the fight a bit longer.

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Consider how many games we will need in order to test the hypothesis if we are talking about an advantage of 60%-40%. Add in the fact that there is no agreement on when the opening ends or what the advantage is. This shapes up to be a rather long thread!

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Another 3d game (picked from browsing kgs game archives until I found 3d vs 3d that didn't end by time, didn't look at the game beforehand):



This one is rather interesting as there was an early ko fight and exchange (though white could have lived without ko at c1!). Should we say the opening ended at move 26, or after the exchange to 46. The latter is near the 50 mark, and might actually give the first game for these statistics. Judging this game takes more time than I have now. Will edit later...

Edit: Lower left black has 20 solid points, lower right shimari let's call 12. r7 area is not points, and top right black group could be attacked by a white invasion at r13/r11 so can't really give black many points there, but equally a white invasion is weak too. Perhaps say of the r11 and r7 area black will get one so lets give him another 8 points on that side somewhere. So black has 40 points territory plus the outside influence of that lower left (and sente). How to value that wall? Hard to say. g4 is not dead stone and could be sacrificed, but as is helps k4/n3 a bit from severe attack so perhaps say black has an extra 5 points in the j2 area for that. d10 can also be isolated by black's 47 so some value in that influence direction too, but also black's invader is weak too. Maybe another 5 points? So let's say black has 50.

White's lower side group is sandwiched between two thick black groups so won't make much, let's say 5 points. White's top right is 16 solid to O row. k18 to n18 area is also likely to be points, about 10? How to value the 3 hoshi stones in top left? Given the game continuation a reasonable estimate would be the top side becomes points, d10 becomes dame. Top side is about a 3x10 block so 30. So white's total is 5+16+10+30+6.5 = 67.5. So white leads by about 17 points +/- 10 or so, but black sente. So I say this game counts as a white lead of about 10 or so. And white won it. So adding this to my tally of results in the 1st post.

Do people agree with my judgement? Maybe I was too generous to white at the top left, and too stingy to black on the right? My gut feeling was white boobed by allowing the ko, but also black made a mistake to ignore the threat as white's compensation was larger.

Well, Often suggested 10,000 games! I reckon we might need 500 KGS 3d games to get 100 with an opening imbalance of >=10 points (which is a relaxation of my 10-15 points in the bet so should increase the win rate). And even then if the hypothesis is a 10+ lead results in a 0.6 win chance rather than 0.5, then the chance of >50 successes in 100 trials of that binomial distribution is 97.3%, versus 46% for 0.5 win chance. And >55 is 86% for 0.6 win chance, versus 13.6% for 0.5 win. And >60 is 46% for 0.6, 1.7% for 0.5.

I had made the two categories of KGS 5k and KGS 3d, with my predicted win rates of 55-60% for a 10 point lead for the 5ks and 65% for the 3ds. If we relax the kyu category to KGS 5k to 1k then I'd expect the win rate for 10+ point leads to increase as 1ks are quite a bit stronger than 5ks, but it's more inclusive. As for your game I agree white is leading at 46, but gut feeling is not sure if 10+? So some counting:

White top left 10, lower side 5, komi 6, right side moyo = ???. Open at s6. Let's say white gets 2 of the 3 areas of corner, side above r10, side below r10 so about 30 points. 51 total.
Black lower left 20, lower right n3 might work so 18, top left only 2 and weak, but also white's group weak so about cancel, top middle 7. 47 total. So white leads, but not enough to count in this experiment. Or was 30 for the white moyo too stingy? Black has basically no potential to make more points other than 2 point invasion groups and l5 to make an extra 10 or so by patching up n3 or e2/h2 to grow a little there and hassle white a bit, whereas the 30 I gave for white's moyo had quite a large error on it. If black goes for reduction and can get p10 for q12 and r17 for r16 then p18 white is reduced to about 35 points on the side. But maybe a deeper invasion can succeed. So if that 30 was 35 then white leads by about 10, and if 40 then more than 10. Do people think white is leading this game if no komi? So I'm not sure whether to count this game in the >=10 lead category.

Ok, here is my experimental design:

1) Get 10 (?) volunteers. Each submits an sgf with the result scrubbed out (and maybe player name/rank)
2) Each of the volunteers goes through each sgf ONLY up to move 50. (This may not be the end of the opening, but we have to pick a line.)
3) Each volunteer predicts Black or white to win.

We now have 10 blind predictions on 10 games = 100 predictions. The null hypothesis is: the opening doesn't matter, so the predictions will be approx. 50% correct. If the predictions are significantly (80%? Who knows) better than random, it would provide support for the "opening matters" hypothesis.

Any volunteers?

I volunteer. But I think volunteers should submit the games only to move 50 to avoid accidentally seeing later parts of the game.

Also, submitted games should be chosen at random. Participants shouldn't choose a game they think is hard or easy to predict.

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