Mirror Go / Discussion

Sub-page of MirrorGo

Some competitions forbid mirror go to exceed a certain number of moves.

(Which competitions do this? And why?)

One reason might be that the mirrorer can save up a lot of time. He can respond quickly to any move that his intuition doesn't scream at, until he has saved up a significant amount of time. At this point he can play the middle game with no disadvantage. -dspivak

unkx80: I wrote this when the tournaments organized by the Singapore Weiqi Association had a clause that forbids mirror go exceeding 60 moves, but I am not sure why. But this clause has been removed.


I have a naive question: it seems to me that playing manego is a decent strategy if your opponent isn't too weak, and if you don't blindly mirror their moves.

It seems to me that you'll be able to keep sente all the time. So far, all of the examples in breaking manego requires some sort of unnatural move (playing at tengen, for example). If I see my opponent doing that, I'll simply ignore him.

On the other hand, if the opponent tries to attack my weak group, he / she would have the same weak group as well, which I simply counterattack. Again, if he / she makes a mistake in defense, I'll simply ignore the move and play elsewhere.

This seems too good to be true, so where's the flaw in my train of thoughts?

Jasonred Huh? Keep sente all the time? I'm not sure why? Could someone explain this to me? I thought that this GIVES sente all the time?

As for tengen, IMHO, the best time to use mirror go is when you're black, THEN play at tengen. There you go, now you can manego LOTS, and be confident that your center is stronger than your opponents.

Now, as to the flaw in your plan, if you play manego as white against me... here's the most obvious breaker: fierce battles in the center, if you're playing white, and have been exclusively playing manego. Or, in fact, in the MOST simplified case, this particular instance.

cross cut  

Basically, ANY fight that is symmetrical, and CONNECTING will result in a win by whoever moved first, I think. Yes, you are equally badly/well off if there are two separate fights/groups, but if there's only ONE... then you WILL lose. (I think)

  • I think this is refuted by the first example here, but perhaps I'm misunderstanding what you mean by "CONNECTING". In this example, Black's extra stone at tengen removes a liberty that he needs.

Now, personally, I think manego DEFINITELY has it's uses, IF YOU'RE PLAYING BLACK. Cause then at least you should be in a stronger position at any given time.

If you're playing white, then black can just lead the fight to the center. Then tengen is gonna be a sensible move after all, and you will WANT to follow, but can't. Either that or he'll atari you such that you can't capture after he does.

The SECOND flaw in manego is this: If you can't be worse off than your opponent, your opponent can't be worse off than YOU. In other words, the BEST you can hope for by pure manego is a draw game. BUT, black needs to beat komi. White needs to overcome the fact that black will win any fights in the center.

adamzero Dave's point is the best one worth making, but if one "does" want to talk mirrorgo strategy, then it is probably not to Black's advantage to play mirrorgo. Black must overcome komi. With every successive move, the size of the remaining moves is lower, and it is harder to overcome komi. Early in the game, nearly every possible move is worth more than six points, and that is when komi is thus most easily overcome.

Jasonred Exactly. Thanks for fleshing out what I was saying about komi, I wasn't 100% clear on what I was saying, but it all seems crystal after your explanation.

Archaic Jason, I think you have a very poor understanding of manego, but nonetheless you point out a lot of basics. However, you shouldn't just dismiss the possibility that it has be an effective counter, and not a weak one. Also, mirror go is not as easy to counter as it seems, I'm not sure if an ordinary complex fight in the middle works that easily, especially since any move you make, the opponent will just respond in the rotational-symmetric direction. That sort of natural approach is definitely recognizable, and might be possible, but try to use a bit of further analysis.

Simply put, instead of basing your thought process on the mere notion that manego and go in general is a fluid, free, and easy-to-understand game without having to analyse specifics before you earn that open-mindedness is just a lack of understanding on a fundamental level.

Now, all this brings up an important thought: How about handicap matches? Like, what if I played a Dan player and got a 9 stone handicap AND reverse komi? Would mirror go work for me then?

I see no reason why not! Even if my opponent breaks it, I would think that he'd have to give up more urgent moves to do so, giving me a chance to go for the jugular. Also, he's got to create territory or try to kill my stones, so I don't think he can "waste" moves by doing that.

Someone else analyse and point out my mistakes please? I'm sure there are some mistakes, or else I challenge some really strong player with this...

Answer: The stronger player just needs to capture one of the handicap stones. His moves will all be meaningful, and his stones will have gotten a liberty, while black's moves will have been meaningless. Put this position on a board, and you will see that any talk of mane-go from that point on is out of the question - the position in the two corners is no longer symmetrical, white has gotten a point (prisoner) but black has not, and white can play on the hoshi point at any time and effectively stop mane-go in any form.

19x19 diagram  

Jasonred Hmmm... IMHO, the biggest skill in Manego is knowing when to stop copying. And possibly, how to resume copying. So, the moment my opponent slaps down move 4, I'd have to respond to the invasion. AFTER that, I would possibly attempt to resume manego... maybe. (despite the fact that it's asymetrical...) Trading a corner for a wall so early on seems like the end to me, despite my being a terrible go player (20 plus kyu?) I'd only use mirror go on a stronger opponent to make up for my lack of fuseki knowledge... OBVIOUSLY, you don't use manego to win in-fighting or pushing games!

Imagist: The fact that W2 is an invasion of a moyo makes even B3 a bad move. W2 gives you a chance to make territory by attacking white's invading stone. While B3 is a natural moyo-solidifying move, it still doesn't do much to prevent white's attachment at B7, and meanwhile white creates a stronghold from which she can launch further attacks. I would guess that a slow play like this already loses the advantage of one of your handicap stones, maybe even 2.

DaveSigaty: Let's see. You have found a stronger player friendly enough and patient enough to play you with 9 stones and a reverse komi. Your strategy is then to play mirror Go. How many moves into the game do you think it will be when your opponent invites you to leave? ;-) When they do, will you count it a success?

Of course mirror Go has place in competitions (like any legal strategy). But what possible point does it have in amateur play? You bring no originality (the approach has been known for centuries). There is no intellectual content unless you believe that it is ultimately unsuccessful and therefore you as the mirroring player must find just the right point to break the symmetry in order to win (actually true in high-level play but probably not for a lot of amateurs). So why bother?

Jasonred True. It's pretty much socially unacceptable. And pretty moronic, as the whole idea of playing stronger players is to learn, and manego doesn't do this. (much... I guess maybe you could learn a little about shape?)

Frankly though, I'd say manego's ONLY use is in ruthless competitions. (other than learning when to break off manego itself) So, I was just giving an example of when I thought that manego would clinch a victory, or be really useful. That was an extreme example anyhow, umm... say you're playing for money, and someone gives you a 2 stone and reverse komi handicap? (Make sure you can fight better than your opponent before trying manego in this situation...)

Having played mirror go a few times against Igowin, I thought I learnt a fair bit. It teaches you to tenuki (every play you make in mirror go is tenuki, unless someone has set up a mirror breaker). It also teaches you to apply mutual damage. So, quite educational.

9x9 Mirror Go Problem

(Sebastian:) How about games against someone one stone below? This does not give handicap, but gyaku komi. Here's an example of a game I just played on KGS. I lost it with 0.5 points. Any hints how I could have prevented this? (BTW, the opponent, MartinX, has quite a proportion of unfinished games. Maybe those were similar games where his opponents didn't know what else to to but escape. Or he's an escaper himself. I'm not sure who broke off those games. Is there a way to tell this on KGS?)

Moves 1 to 10  
Moves 11 to 19  

At this point, after B19, I realized that Black was playing mirror go. Was this too late or could I still have saved the game?

kevinwm: To me, F5 seems to be an obvious way to break the mirror. w can't play D5, and should defend F4.

ThorAvaTahr: black is playing mirrorgo.

Moves 20 to 29  

white+circle = W20

Moves 30 to 39  

white+circle = W30

Ilja? You could have saved it.

Moves 20 to 29  

20-23 to enclose the tengen. After this, the tengen gives no longer any advantage. 24-27 to disconnect the central group from its neigbours. Now try to kill the black central group without defending your own central group.

Moves 30 to 39  

9x9 Good Example

OK, I played another game with Mellow, who kindly agreed to try it out. Here's how he forced me to resign:

Moves 1 to 10  
Moves 11 to 20  

I wonder what I can learn from his play. In particular, my problem in the game with MartinX was that I did not realize that he was playing mirror go till move 19. Could I still have saved it at that time?

Zarlan: Of course. You should have played 21 at a and put his middle group in atari.

(Sebastian:) Sorry about the confusion: My game with MartinX is the previous one. This is the game with Mellow, which I resigned at move 21 because of a.

blubb: Agreed, the above situation does not really look appealing to the eye. :) Anyway, now that we are at it, what about this?

Moves 11 to 20, a next  

As far as I can see, B is still likely to lose here, due to the additional idle stone in the center, and W can connect above. However, this would not have been an immediate "must resign" to you, I guess.

Mirror Go got my attention because of a remark of Bill Spight in 1997. He said that modern high komi - as for example in Ing rules - are an incentive to play Mane Go as White: "... just to lower the temperature." After that episode I started to use mirror Go in one of my games as White in each and every tournament, but playing ordinarily in all other games. To state the conclusion first: I do not regret this decision, and my experience with this experiment up to date is very positive.

First of all, mirror Go slows me down. At every move I have to check if either Black can play Tengen with devastating effect now or in the near future, or if I can depart from mirroring with an advantage for White. This sort of thinking is completely different than what's going on in ordinary games, but it is nevertheless quite challenging.

As I have come to get accustomed to mirror Go, it is now slightly more likely that Black plays Tengen before White departs. And more often than not my black opponents lose their nerve before I do so, resulting in a play at Tengen before it is effective or in a misplaced stone somewhere else so that White can depart advantageously. Mirror Go is thus quite an effective battle strategy for me.

Besides, mirror Go games are also very interesting after the mirror phase has ended, which ever way. Sometimes it's really hard to switch back to "normal mode" and analyze the position in the usual manner. Obviously, most of the time the game will be very close, sometimes with many open ends and urgent plays all over the board. In this phase I get the opportunity to play types of positions I never get in in an ordinary game. I have to continue with stones and josekis I would never have played myself. All sorts of unusual and unexpected stuff happen in mirror Go games. This broadens my Go-horizon quite a bit.

In most games the mirror phase is rather short anyway. Very rarely does it last more than 20 stones. Then, most of the time the mirror phase ended with a black stone on Tengen and two huge moyos for both players. This is another type of game I practically never play myself, as I am extremely territory oriented.

Above all, trying mirror Go every once in a while is fun - especially when you notice that the black player has not the slightest idea what to do about it :-) But two things did never happen in my career as mirror Go-player: Mirror Go never helped me win a game by lowering the temperature so substantially that the white komi won the day, and never did Black continue to play mirror Go against me after Black played Tengen. - GoldenBear?, 3 Dan, May 2004

blubb: I agree with your points. Moreover, I do not even think mirror Go necessarily has to be treated like something entirely different from whatever we call "normal Go". Often when a position or the concept in general is discussed, the mirroring party is assumed to blindly keep on mirroring each of our moves. Why so? Similarly, when the social implications of mirroring are talked about. Mirroring is often frowned about as being dull, uncreative, unchallenging and whatnot. Again, why? Neither seems necessary, not even reasonable to me. Mirroring a bad move is questionable, but when a particular move in a symmetrical situation is good, the mirrored counterpart quite naturally is a candidate to consider, too - even though it may be far out at the "extreme tenuki" end on the scale of styles. Of course, pure mechanical mirroring indeed requires no creativity, no sharpness, and hardly any other skill that Go is usually associated with. But there is plenty of interesting possibilities on the way between that and strictly non-mirroring play, rather than a Chinese wall. The 1973 Kato Masao vs. Takemiya Masaki game mentioned at Karami`s page looks like a good example to me.

In China, mirror go is called 东坡棋 Dong1 Po1 Qi2. And there is a story about it.

It was Sung dynasty (perhaps about 1100 AD) in Chinese history. Su1 Duong1 Puo1 was a talented poet, artist, scholar....but very weak go player. Su was very creative, and enjoyed challenging any rules. In Chinese painting, traditionally the primary ink was black. Once Su painted a picture about a bamboo forest, which was very common in Chinese painting. However, he used red ink, which had never happened before. When friends questioned him: Have you ever seen a red bamboo? He replied: Have you ever seen a black bamboo?

One day, Su claimed he could beat a very strong go player. Everybody thought he must be joking again. Anyway, the strong player agreed to play Su a game. I don't know the result of the game, but from then on, mirror go was called Duong1 Puo1 Chi2 (duong puo's go)...... :)

So, brasenly or not, mirror go is an accepted strategy in Chinese tradition of go.

The following is moved from Chinese Go Terms.

(Sebastian:) Is 东坡棋 (dong1 po1 qi2) named after 子瞻, and why?

unkx80: I have looked up the Internet, and found that it is because it was a clever strategy Su Dong Po (苏东坡) used. Some sources say that he bragged that he can never lose, so when others did not believe and played against him, he simply mirrored and always achieved a draw (territory scoring), hence although he never won anyone, he never lost anyone either. Other sources put it that whenever he played black, his first move is always the tengen and so wins every such game by one point (area scoring).

(Sebastian:) I was doubtful because it seems a bit cheap for a great mind like him. But if he did it to trick braggards, then it would fit his sense of humour.

(Uagi?) One question: isn't it enough just ONE viable strategy for Black and one for White to fight agains mirror go (taken from pro games or from individual analysis)? After all is the one who is not mirroring that decides all the play.

Imagist: On Gobase, one of the Go Seigen - Kitani Minoru matches in which Go played manego has commentary by Go that "Mimic go is really not a very profitable strategy. The opponent gets the initiative and he can choose the opening he prefers." The game can be found [ext] here. Considering that he said this after playing mirror go as black pre-komi, I can hardly believe that mirror go is a viable strategy for black now that there is komi.

Archaic: Maybe it's sometimes easy to and confuse yourself into thinking mirror go is all about analyzing counter-moves. But, don't overlook the fact that it *might be* possible to play naturally and figure out a way yourself to break the person copying your move in a live game without having to over-analyze. Maybe it's possible if you try it yourself, but i'm not sure since I haven't had many chances to play mirror go since amateurs tend not to play it for some reason.

Also, the countering mirror go page is missing the counter-tactic used by a pro to convince fujisawa hosai that his mirror go domination record in japan back then using white with komi wasn't invincible. This counter-tactic namely involved using an odd number of groups (3 each) and scattering them then eventually using tengen to split apart the groups or something like this. This resulted in the best hard-counter winning strategy I've seen, don't remember the source link. It's possibly also missing the softer counter where you just form a moyo as black with tengen but hopefully not using all star points, because white would then just invade and win by komi, probably something more around the lines of playing 3rd line low territory before hitting tengen.

Also, it's kind of confusing as to how white can actually counter black's mirror during the days when there was no komi for white since white did not have access to the tengen which black would occupy. All in all, probably just a more complicated process for white. Actually, I believe recently a high dan told me that it's relatively easy actually and I somewhat understand it better but it might come down to a close counting game or involve capture tactics.

edit: For example, somebody told me that more often than not for amateurs at the very least, settling the rest of the board in the opening first before swirling to the center as black and using tengen to create a winning conflict can overcome the komi that white begins with. On the flipside doing so with white and then attaching to tengen to create a conflict works as well *even* if white does not have komi such as back in ancient times. This credit goes to a 5d-6d player on kgs. It may or may not be correct.

Also, mirror go is only limited if you think about it and does not work in theory, the general purpose is to copy the opponent's moves in an attempt to score a rather even game, or wait until he makes a mistake and you break off to get the lead as a sort of imitation/copycat/annoyance technique. Eventually though at a certain point, Go probably eventually becomes more about general strategy and not about mirror go other than the possibility that for pros white can use komi to his advantage. This is because it does not make sense for mirror go to have the utmost importance in Go or be the ultimate strategy. Black does not do mirror go for the sole reason that there is no reason to :/ other than copy moves hoping to catch a mistake and break off, but white has komi and also the above-mentioned tengen attach after settling the empty board first which is disadvantageous to him. But, as is obvious, due to initiative and sente the mirrorer is naturally at a disadvantage.

In the days without komi black being able to mirror white just gave him all the more advantage to be able to try to draw the game against a stronger opponent on top of the lead he had without komi. So nowadays with komi the mirrorer usually mirrors with white instead of black probably and it's more balanced, since black can counter easily with tengen so he doesn't mind either. It probably also gives a more interesting twist to mirror games involving komi use rather than the strict mirror implementations probably found in past games without komi (such as how it was probably less likely for white to mirror black and also how white had a much harder time dealing with black mirroring him because of the complexity involved when white lacks komi on top of tengen and has to find a complex method to deal with this).

Cuc?: The game theoretic question is interesting, as we like to know if there is a winning strategy. When I read the traditional story (I forgot in what book, can anybody give a reference?) I believed that the strategy was in fact a winning strategy, but later I realized by my own experiments that it was flawed. As other players have commented, if Black wants to win, he has to depart from playing manego.

Above we saw that in an even game, Black will lose at least one center fight and gets behind. With komi for White, Black will lose unless he departs manego.

Another interesting question from Archaic was what happens if Black gets 9 handicap stones and reverse komi. I proved for myself that if the manego is followed, then White will win, no matter how high the komi (unless the komi is more than 361 points)! Adopt the following strategy (outline):

- White will capture the middle handicap stone and 4 other handicap stones of his choice.

- White solidifies his eyes by connecting his stones around the eyes.

- White will connect his groups any way he can. NOTE. White now has one living group connecting all over the board.

- White will capture the black group.

If at this stage it is agreed that white has won, the game is over and Black lost the game. If play is insisted, White can continue to kill ALL of Black's stones!

- White can capture each of Black's groups one by one in any order he chooses such that none of his own groups are captured. Basically, all of White's stones will always be connected, while Black's stones are disconnected and form dead groups.

- At certain moves in the continuation of this strategy, Black can not mirror White when White captures one stone, because it would be suicide for Black. In this case Black passes (small deviation from the main strategy, but Black gets even more behind with this).

- When all groups of Black have been captured, White scores 361.5 points minus the reverse komi. Hence, White wins.

Illustration of this strategy:

Moves 74 to 83  
Moves 202 to 211  
Moves 265 to 274  
Moves 342 to 351  
End position  

Mirror Go / Discussion last edited by Cuc on March 30, 2015 - 06:51
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