Opponent mirrors your moves

[Bill Spight]

Another intersting topic, courtesy of PeterPeter!

There was a famous mirror go game between Kitani and Go Seigen. I'm in a hurry, or I would find it and post it here.

Basic mirror go strategy:

Return to even.

I have not heard anyone complain about nirensei vs. nirensei.

Basic mirror go counter strategy:

Keep the temperature high. (Or even raise it.)

Eventually the mirror breaks (we hope!). When it does, you should be the one who makes a big play that either captures or kills some stones, or plays a sente such that after your opponent replies, you get the corresponding reverse sente, which is large.

(;ST[2]SZ[6]CA[ISO8859-1]FF[4]AP[GOWrite:2.2.21]GM[1]FG[259:]PW[ ]PM[2]PB[ ]GN[ ]
;B[dc]
;W[cd]
;B[dd]
;W[cc]
;B[ce]
;W[db]
(
;B[bd]
(
;W[ec]
;B[cb]
)
(
;W[bc]
;B[eb]
;W[be]
;B[bf]
(
;W[ae]
;B[de]
;W[da]
;B[ea]
;W[cb]
;B[cf]
;W[ad]
;B[af]
)
(
;W[ec]
;B[ae]
;W[ed]
;B[de]
(
;W[cb]
;B[fb]
;W[ee]
;B[ef]
;W[fe]
;B[df]
;W[ea]
;B[ff]
;W[da]
;B[fc]
)
(
;W[fb]
;B[cb]
;W[ea]
;B[bb]
)

)

)

)
(
;B[eb]
;W[be]
;B[de]
;W[cb]
;B[ea]
;W[bf]
;B[cf]
;C[*** How NOT to play ]W[da]
)

)

Mirror go on the 6x6.

Edit: Can't this thing show a 6x6 board?

[Dusk Eagle]

I don't think Eidogo supports anything other than 9x9, 13x13, and 19x19.

[Twitchy Go]

As long as neither of you played Tengen, he/you cannot capture a group without letting you/him also capturing one. That's mirror Go ; ) If Black has already a stone on Tengen then attaching is the simplest to break the mirroring.

But yeah, I also think mirroring is cheap.

my emphasis.
I'm going to disagree with you SoDesuNe. I enjoy playing mirror go as white and have played against it a few times as black, and it is a tough game for both sides.
Black needs to play good moves that don't give white a chance to deviate with a profit, and work towards some way to break the mirror and avoid losing by komi, i.e. double ladders, moves around tengen. With a single slow or bad move white will deviate.
And White isn't just blindly copying. Every move he needs to decide if it is best to continue the mirror or if breaking it is more profitable. This is done by evaluating blacks play in regards to the whole board. White also needs to be on the lookout for potential mirror breaks. I find I use more time thinking as the copier than the copyee.

I've never had experience with black mirroring but it seems like it would work the same way.

I think mirror go makes the game temperature very high and leads to a tense game. Especially because for as long as the mirrorer is sticking to his strategy, sente doesn't exist. Mirroring is a tenuki based strategy after all.
And this is why people don't like playing mirror go I think.

But back to the OPs question.
Regardless of the mirrorers strength you should keep playing the best move. Ideally they are looking for a chance to break and take advantage of your mistake. However your question sounds like they are mirroring you regardless. In that case the easiest method is to steer the game towards the center so that tengen(or a nearby point) becomes a good move/mirror break. It is important not to do this to early because in effect tengen can end up being the bad move that white was waiting for.

[Twitchy Go]

http://www.lifein19x19.com/forum/download/file.php?id=2834

Here is the game Bill was talking about.

[SoDesuNe]

As long as neither of you played Tengen, he/you cannot capture a group without letting you/him also capturing one. That's mirror Go ; ) If Black has already a stone on Tengen then attaching is the simplest to break the mirroring.

But yeah, I also think mirroring is cheap.

my emphasis.
I'm going to disagree with you SoDesuNe.

That's okay ; ) I still think it's cheap. It has nothing to do with how viable it is as a strategy or how much complex thinking one assumes is behind each mirroring move. I have also no problem playing against it, I will just break it at the first good opportunity.

For me it fits the same category as being over-aggressive or playing Hamate, both will mostly end badly when one responds correctly.

[SmoothOper]

Mirror, go is possibly more annoying than aggressive approach move go.

I had a situation where I was playing on IGS as white without komi, because they were weaker, black played the first move on tengen, so complimentary ladders didn't work either. That was annoying. Essentially you have to start four ko fights then play through the cycle until they can not recapture, because you take first.

[palapiku]

Mirror, go is possibly more annoying than aggressive approach move go.

I had a situation where I was playing on IGS as white without komi, because they were weaker, black played the first move on tengen, so complimentary ladders didn't work either. That was annoying. Essentially you have to start four ko fights then play through the cycle until they can not recapture, because you take first.

You can simply surround and capture the tengen stone.
See here: http://senseis.xmp.net/?CounteringMirrorGo

[Insane]

Cho Hye-yeon wrote about mirror go in her blog five years ago: http://loveku.livejournal.com/22137.html

[SmoothOper]

Mirror, go is possibly more annoying than aggressive approach move go.

I had a situation where I was playing on IGS as white without komi, because they were weaker, black played the first move on tengen, so complimentary ladders didn't work either. That was annoying. Essentially you have to start four ko fights then play through the cycle until they can not recapture, because you take first.

You can simply surround and capture the tengen stone.
See here: http://senseis.xmp.net/?CounteringMirrorGo

As is stated in that article, the problem is if black breaks from the mirror prematurely, white could be left with bad aji.

[zslane]

The technique for breaking mirror Go against black who plays on the Tengen was admirably demonstrated in episode 8 of Hikaru no Go. Okumura, a junior high school member of the Kaio Go club, thought he could humiliate Akira Toya by playing mirror Go against him, and quickly learned the futility of it.

http://www.dailymotion.com/video/xwnob_ ... UUZ54y9KSM

The incident begins at the 7:30 minute mark, and the center break sequence of moves begins at the 10:00 minute mark.

[Amelia]

Yeah, I remember that, too. Though in this case, there's a huge difference in skill between both players (the weaker player had to keep mirroring to the end to win. A stronger player would have broken the mirror and then kept playing after the tsuke).
And it seems to be a game without komi.

[zslane]

Yeah, I remember that, too. Though in this case, there's a huge difference in skill between both players (the weaker player had to keep mirroring to the end to win. A stronger player would have broken the mirror and then kept playing after the tsuke).
And it seems to be a game without komi.

Yes, Okomura had to keep mirroring to have any chance in the game, but at the same time, he blindly believed that doing so would work against any opponent, even one as strong as Toya.

I assumed they were playing with the usual Japanese komi of 5.5 moku. Did I miss something? I don't think we're meant to interpret Okomura's claim of "I can't win, but I can't lose..." too literally, in the sense that he expected an actual draw.

[gogameguru]

When asked about this game between Kim Jiseok and Kang Dongyun last year, Lee Sedol said:

"Yes, I saw the game. I didn't really think of it as mirror Go because those moves were really the best choices Kang Dongyun could make in that opening. And, personally, I don't play mirror Go because it's difficult to win when playing that way. If it was a good strategy I'd use it, but, in fact, it's not."

This is a video of the interview with English subs for anyone who wants to watch it: http://gogameguru.com/baduk-tv-videos/b ... altex-cup/

Unfortunately this one was hard-subbed by Baduk TV early on and we never got access to the transcript to edit it. So the quality of the translation isn't as good as usual, when we do it entirely by ourselves.

[xed_over]

Yes, Okomura had to keep mirroring to have any chance in the game, but at the same time, he blindly believed that doing so would work against any opponent, even one as strong as Toya.

you realize that they used actual pro games as props for the Hikaru story?

I don't have the books in front of me, so maybe that wasn't so much of a game, as it was an example position.

[hyperpape]

Here you go, xed: http://rongen17.home.xs4all.nl/Hikaru/index.html. The mirror go game was very short, and obviously not a professional game.