So many variations and repeated KO (2x2 game analysis)

Dear masters of the game,

I tried to put some moves on this board, thinking that at least a 2x2 game I could understand. Ahahaha

But, no… Sooner than I thought, the variations opened to a lot of options, some of them gives “illegal repeated position” in a “not-so-obvious” ko that may have a cycle longer and a “simple 1-cycle ko”.

It is amazing how the game opens up…

Forget about the “komi” or other topic about “cheating” (too funny). Please, just focusing on the game and the moves in this thread: can you help me put some order into the chaos? Trying to visualize the outcomes.

Questions like:

  • Without Komi, who would win? Is there a side that would forcibly win?
  • First move doesn’t matter, but suppose it is B1.
    • If white play other than A2, black wins. Simple.
  • Now, white play in the diagonal, A2.

Is this position “seki”? Is the best move for both just to “pass” and end the game?

And the crazy stuff: if this game goes on and on, will it ever end?

It appears that after we repeat all 4 possible boards with only one black and the rest empty (black on B1 as start position, then some captures resulting in only one black on B2, then again, one single black on A2, then again, one single black on A1…) we reach this position:

And it becomes illegal for black to play again on B1 because it would repeat the very first board position. What is this repetition? Is it a kind of ko? And who wins in this final position?

Thanks a lot!


Dr. Bèco

Analysis graph:




Very interesting.


Why white passes on move 10?

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I can’t even imagine a meme that could contain not only koing, but superkoing oneself.


Sorry, @Gia but:



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The Chinese rules with ‘Super-Ko’ make the only available spot (A2) an illegal repetition. You can try it in analysis mode in the game.


I believe this 2x2 board is the best way to learn about ko and super-ko ! :heart_eyes:

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You can find a very helpful detailed explanation here Question about illegal move by @_KoBa


John Tromp had calculated the number of possible games on a 2x2 board (under the Tromp-Taylor rules of go) as being 386,356,909,593

Many variations indeed! Despite there only being 57 legal positions, there are over 386 billion possible ways to cycle through them in legal games.


Mind = blown. O__O

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