Alter Igo Endgame Problems / Problem 1 Solution
This is the solution to the Alter Igo endgame problem 1.
![[Diagram]](../../diagrams/4/df1cef07a4fbe5f2d687b271328563ef.png)
Problem 1
The question was, what is the best move for either color, and what is the result then.
![[Diagram]](../../diagrams/8/f24c621c149573fb935e359364dee012.png)
Solution 1b (black first), moves 1-2
is the vital point.
is white's strongest resistance. Notice that
will get removed as well.
White does not want to play at the upper left corner, because that would give black a fourth eye. So white persists on the right.
![[Diagram]](../../diagrams/12/30177290d80501ab2b1936adf0de33a1.png)
Solution 1b, moves 10-13
After black 11, white must fill an eye, so black captures at 13 and wins.
![[Diagram]](../../diagrams/49/a83bf6d9f2d35f6f0d785016b61614f0.png)
Solution 1w (white first), moves 1-2
White should also begin with
. Black must respond, or his stones will die in a collapsing seki. (Variations given below)
However,
is a powerful tesuji. (In fact, it is so powerful that even the creator of the problem did not realize how powerful it was.)
![[Diagram]](../../diagrams/22/4d1a436ec6cede8f5daf05f8f1a62fb5.png)
Analysis: collapsing seki.
elsewhere
Notice how
removes also the 2 black stones. Also note that a black play in the lower left corner would have self-captured black's main group too.
![[Diagram]](../../diagrams/52/4c63db4ea4e2f44df87e318fe044d5e4.png)
Analysis: collapsing seki.
elsewhere.
White can force a mutual capture even if black has moves elsewhere.
![[Diagram]](../../diagrams/12/c1102c70282560015060dec1dd1a2e29.png)
Solution 1w (white first), moves 3-5
![[Diagram]](../../diagrams/25/9c952e9cb9b93701965945471b49d722.png)
Solution 1w (white first), moves 6-7
Now it is important to notice, that black can always "waste a move" in the upper left corner, that is, he can play there, and end with sente and an eye. This enables black to kill:
![[Diagram]](../../diagrams/37/c8ac6eddec8ab0b916f6148e873e79dd.png)
Solution 1w (white first), moves 8-11
![[Diagram]](../../diagrams/6/ae1adfd3d9dbe39efdd0f4f0062d6c65.png)
Solution 1w (white first), moves 12-14
![[Diagram]](../../diagrams/46/3bbe0193100fb35a5eed9d229ad43295.png)
Solution 1w (white first), moves 15-18
So even if white plays first, black still wins because of his three-space eye with 2 prisoners inside. Not quite what I thought when I created this problem a couple of months back!