I agree that if White has a weaker fuseki and stronger middle game than Black, than playing mirror go at the beginning of the game can be a good strategy. But in the absence of information, if Black always tries to play the best move (and not some anti-mirror strategy), then the best choice for White is to try to play the best move, and not the mirror image of the previous one, which is generally suboptimal.Bki wrote: Your reasoning is kind of weak here. "Serious" mirroring isn't about playing mirror until your opponent play tengen or some other anti-mirror go strategy, but to do so until you can get an advantage by breaking the symmetry (or I guess, start the middle game with a roughly even position if you're not confident in your fuseki), or until black play a premature anti-mirror move that give you an advantage.
What about mirror go?
-
jlt
- Gosei
- Posts: 1786
- Joined: Wed Dec 14, 2016 3:59 am
- GD Posts: 0
- Has thanked: 185 times
- Been thanked: 495 times
Re: What about mirror go?
-
Uberdude
- Judan
- Posts: 6727
- Joined: Thu Nov 24, 2011 11:35 am
- Rank: UK 4 dan
- GD Posts: 0
- KGS: Uberdude 4d
- OGS: Uberdude 7d
- Location: Cambridge, UK
- Has thanked: 436 times
- Been thanked: 3718 times
Re: What about mirror go?
Mirror go as white with komi, if played skillfully rather than just blindly mirroring, is an interesting strategy and not so easy to refute. The basic premise that white is seeking to exploit is that if mirroring continues in such a way that each get the same territory away from the centre and tengen becomes dame (or rather less valuable than komi) then white will win. So the onus on black is to steer the game in a direction that tengen becomes more valuable than komi. There are several ways to do this:
- use it to make some centre territory
- use it in a tactical sequence so they run out of liberties before you. This can be done centre fighting sequence or opposite ladders.
- make some fight so that it's useful. It doesn't actually have to be exactly tengen, sometimes nearby points work too in that sente is super valuable if White keeps mirriring, overlaps with tactic above
- make it tedomari
So if White sees Black's play leading to this he has to stop mirroring. Black has to be wary of playing tengen too early just to frustrate White's mirroring plan as it may be a bad move, and White then can't mirror but just plays a more valuable move than tengen and takes the lead. Also with a clock I think it's quite an effective strategy as black needs to put a lot of time and effort into a plan to make tengen valuable but White can generally play fast and think in black's time.
Fujisawa Hosai/Kuranosuke famously played mirror go as white even before Komi (but slowly). There are some excellent articles in GoGoD about how some pro, Yamabe iirc, finally convinced him it was refutable with some pretty deep two moyos colliding with tactical sequences collapsing the mirror ideas. This was after Fujisawa had been playing mirror go for decades. But such an idea is harder to construct than double ladders.
Here's a mirror game I played on OGS some years ago against one of the top players there after studying the GoGoD mirror articles and some of Fujisawa's games, in fact for I think for quite some moves we were playing the same as a game of his.
https://online-go.com/game/372110
- use it to make some centre territory
- use it in a tactical sequence so they run out of liberties before you. This can be done centre fighting sequence or opposite ladders.
- make some fight so that it's useful. It doesn't actually have to be exactly tengen, sometimes nearby points work too in that sente is super valuable if White keeps mirriring, overlaps with tactic above
- make it tedomari
So if White sees Black's play leading to this he has to stop mirroring. Black has to be wary of playing tengen too early just to frustrate White's mirroring plan as it may be a bad move, and White then can't mirror but just plays a more valuable move than tengen and takes the lead. Also with a clock I think it's quite an effective strategy as black needs to put a lot of time and effort into a plan to make tengen valuable but White can generally play fast and think in black's time.
Fujisawa Hosai/Kuranosuke famously played mirror go as white even before Komi (but slowly). There are some excellent articles in GoGoD about how some pro, Yamabe iirc, finally convinced him it was refutable with some pretty deep two moyos colliding with tactical sequences collapsing the mirror ideas. This was after Fujisawa had been playing mirror go for decades. But such an idea is harder to construct than double ladders.
Here's a mirror game I played on OGS some years ago against one of the top players there after studying the GoGoD mirror articles and some of Fujisawa's games, in fact for I think for quite some moves we were playing the same as a game of his.
https://online-go.com/game/372110
-
jlt
- Gosei
- Posts: 1786
- Joined: Wed Dec 14, 2016 3:59 am
- GD Posts: 0
- Has thanked: 185 times
- Been thanked: 495 times
Re: What about mirror go?
In the game you posted, you stopped mirroring at move 18, but things went better for Black only at move 34. Hard to conclude anything.
- Capture.PNG (73.8 KiB) Viewed 11444 times
Re: What about mirror go?
This claim could use some proof though.jlt wrote:if Black always tries to play the best move (and not some anti-mirror strategy), then the best choice for White is to try to play the best move, and not the mirror image of the previous one, which is generally suboptimal.
If B plays perfectly (and no anti-mirror), then by mirroring W may maintain a lead of 7.5 points - up to the point where stopping mirror is advisable for center-related reasons. This is more than could be reasonably expected: slowly eroding those 7.5 to compensate for B's advantage throughout the game (arriving at +.5 by yose).
OC B's center potential may grow quietly and unnoticedly, so in practice the 7.5 is not really maintained by mirroring either.
-
jlt
- Gosei
- Posts: 1786
- Joined: Wed Dec 14, 2016 3:59 am
- GD Posts: 0
- Has thanked: 185 times
- Been thanked: 495 times
Re: What about mirror go?
As I said, of course if Black plays a perfect opening, or at least a much better opening than White, then White should play mirror go for a while. But if White is at least as good as Black, then White shouldn't mirror (*). For instance, if White is also a perfect player, then (by definition) the mirror image of Black's last play cannot be better than the perfect response.
(*) Possible exception: if time is limited, White may want to save thinking time for the middle game.
(*) Possible exception: if time is limited, White may want to save thinking time for the middle game.
Re: What about mirror go?
OC W cannot be better than by perfect play on his own - but why should he be necessarily worse off? In particular, why should mirroring perfect play necessarily lose at least 1 pt by move 20-30 or so?
-
kvasir
- Lives in sente
- Posts: 1040
- Joined: Sat Jul 28, 2012 12:29 am
- Rank: panda 5 dan
- GD Posts: 0
- IGS: kvasir
- Has thanked: 25 times
- Been thanked: 187 times
Re: What about mirror go?
There are many ways to counter mirror go early in the game by for example creating ladders or making tengen a big move. It is harder to achieve this later in the game because the board is more crowded and because the middle game is less forgiving then the opening. Some special plan involving ladders or what not might be OK in the opening because the value of many moves is similar but in the middle game the best move starts to stand out and there are less good options.
If there is a limited window in the early game to counter mirror go strategies with a special strategy then one strategy by black could be to play into a wild middle game situation making it hard to impossible to break mirror go but only at the last moment play tengen and play mirror go himself from that point to the end
If every other move in the game cancels out and even a weirdly timed tengen move is at least 7 points then black wins, right?
If there is a limited window in the early game to counter mirror go strategies with a special strategy then one strategy by black could be to play into a wild middle game situation making it hard to impossible to break mirror go but only at the last moment play tengen and play mirror go himself from that point to the end
If every other move in the game cancels out and even a weirdly timed tengen move is at least 7 points then black wins, right?
-
Schachus
- Lives with ko
- Posts: 211
- Joined: Wed Jul 01, 2015 11:02 am
- Rank: KGS 1k EGF 2k
- GD Posts: 0
- KGS: Schachus12
- Has thanked: 16 times
- Been thanked: 62 times
Re: What about mirror go?
I have a slightly different, though similar perspective on what would be the point of mirror go: Typically, you get a slight advantage from having the initiative in a local sequence, i.e. if both sides play the same number of moves alternately in the same region of the board, locally, the player who comes first should get the slightly bigger piece of the cake. Of course this is only small difference, but small differences can add up.
To Illustrate this, have a look at the following joseki:
Modern AI would play differently for white, but humans considered this even for a long time even though both players played the same number of stones(3) and black secured just a little bit more points than white with them. To me, this is explained by the fact that black deserves a little bit more just for being there first. It also goes in line with the common wisdom to first take empty corners, than approach others. If you play a game having black take the first, white approaching, then this joseki finishing in black sente, then black taking the next corner, white approaching and so on, unsurprisingly Elf gives 88% for black after the joseki is played in all for corners.
what does this have to do with mirror go? Now white gets komi, because black plays first. What does black get? He doesnt get more corners, in which he can have the first move, bacause 4 is even, which mans the 4 coners are miai, both get to start in 2 of them. The advantage of playing first comes now: black gets to approach/invade(in newfound AI 3-3 style), which is generally something considered to be "moderately sente", i.e. something you want to react to. Then a joseki of some kind will be played. You might say, what is the big deal, now white approaches one of blacks corners and they a similar joseki there with colors reversed.
This is true if white gets sente from the first joseki, but also black might get sente and use his next move maybe to protect his corner, so white doeosnt get to approach it in a state, where there is one black stone , but there already are two. And there it is the microscopic gain of playing first in a corner. In the same way, It is also a slight bit better for to have b-b-w-b-w-b-...-w ending in white (so locally one stone more for black) than b-w-b-w...-b ending in a black play (also locally one more move for black), i.e. being the "first" to play the second move in a local situation.
Which means white might give up just a little bit in order to take sente in the first corner black approached, so as to be able to approach one himself and so on..
Now another idea for white would be to say: I dont think your approach is sente. Yes, locally you threaten to do something, but I`ll just approach another corner and threaten something of similar size. That way, I preempted your attempt to be first in both places. But, if white does that he needs to make sure his threat really is as big as the other one, so that mutual damage would be okay for him.
Mirror go does just that: answering blacks initiative move with another initiative move of the same size: its mirror image. Of course this works only as long as the battles are local. Once they spread out to the center, white needs to be careful, because the "you do something here, I do the same thing to you there" concept doesnt work, once black gets to do things first, that help in BOTH fights.
I personally have problems against mirror Go with black in the 9x9 games I sometimes play on Go quest. I would be less scared on 19x19, cause I have much more time, to plan out, how I can drag the battle in the center, while on 9x9 it happened to me multiple times, that I took the left side and white got the right one, and the center is dame - I lose.
To Illustrate this, have a look at the following joseki:
Modern AI would play differently for white, but humans considered this even for a long time even though both players played the same number of stones(3) and black secured just a little bit more points than white with them. To me, this is explained by the fact that black deserves a little bit more just for being there first. It also goes in line with the common wisdom to first take empty corners, than approach others. If you play a game having black take the first, white approaching, then this joseki finishing in black sente, then black taking the next corner, white approaching and so on, unsurprisingly Elf gives 88% for black after the joseki is played in all for corners.
what does this have to do with mirror go? Now white gets komi, because black plays first. What does black get? He doesnt get more corners, in which he can have the first move, bacause 4 is even, which mans the 4 coners are miai, both get to start in 2 of them. The advantage of playing first comes now: black gets to approach/invade(in newfound AI 3-3 style), which is generally something considered to be "moderately sente", i.e. something you want to react to. Then a joseki of some kind will be played. You might say, what is the big deal, now white approaches one of blacks corners and they a similar joseki there with colors reversed.
This is true if white gets sente from the first joseki, but also black might get sente and use his next move maybe to protect his corner, so white doeosnt get to approach it in a state, where there is one black stone , but there already are two. And there it is the microscopic gain of playing first in a corner. In the same way, It is also a slight bit better for to have b-b-w-b-w-b-...-w ending in white (so locally one stone more for black) than b-w-b-w...-b ending in a black play (also locally one more move for black), i.e. being the "first" to play the second move in a local situation.
Which means white might give up just a little bit in order to take sente in the first corner black approached, so as to be able to approach one himself and so on..
Now another idea for white would be to say: I dont think your approach is sente. Yes, locally you threaten to do something, but I`ll just approach another corner and threaten something of similar size. That way, I preempted your attempt to be first in both places. But, if white does that he needs to make sure his threat really is as big as the other one, so that mutual damage would be okay for him.
Mirror go does just that: answering blacks initiative move with another initiative move of the same size: its mirror image. Of course this works only as long as the battles are local. Once they spread out to the center, white needs to be careful, because the "you do something here, I do the same thing to you there" concept doesnt work, once black gets to do things first, that help in BOTH fights.
I personally have problems against mirror Go with black in the 9x9 games I sometimes play on Go quest. I would be less scared on 19x19, cause I have much more time, to plan out, how I can drag the battle in the center, while on 9x9 it happened to me multiple times, that I took the left side and white got the right one, and the center is dame - I lose.
Last edited by Schachus on Sun Nov 10, 2019 10:30 am, edited 2 times in total.
-
jlt
- Gosei
- Posts: 1786
- Joined: Wed Dec 14, 2016 3:59 am
- GD Posts: 0
- Has thanked: 185 times
- Been thanked: 495 times
Re: What about mirror go?
I didn't say that... In fact nobody knows if mirroring perfect play loses nothing, or 1 point, or more. Nevertheless, if you have two procedures A and B, and if procedure A produces an equal or better result than B, then you should use procedure A.jann wrote:why should mirroring perfect play necessarily lose at least 1 pt by move 20-30 or so?
Here, procedure A is: choose the best move you can think of. Procedure B is mirroring.
I would even say that mirroring is psychologically risky for White because White might be tempted to copy the move without much thinking, when a better move would be available. On the other hand, mirroring also has psychological effects on Black, since Black might be angry at being mirrored, or might be tempted to use a suboptimal anti-mirror strategy.
Of course, these psychological aspects don't exist when one of the players is a bot.
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: What about mirror go?
Mirror go by the second player on the 3x3
Difference game setup
Best play by Black, who did not mirror
Black wins.
Best play by White, who did mirror
Jigo. White does not win.
Therefore, mirroring the first move on the side is not good.
(As though we didn't know.
)
But note that komi is irrelevant, because komi on the second board is the negative of komi on the first board. Komi - komi = 0.
Difference game setup
Best play by Black, who did not mirror
Black wins.
Best play by White, who did mirror
Jigo. White does not win.
Therefore, mirroring the first move on the side is not good.
(As though we didn't know.
)But note that komi is irrelevant, because komi on the second board is the negative of komi on the first board. Komi - komi = 0.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.