#1 · ypercube
1 Nov 2011
What is the only winning move for Blue here?
Public forum discussion.
1 Nov 2011
What is the only winning move for Blue here?
1 Nov 2011
Nice position.
Only Northwards!
1 Nov 2011
That is cute. It reminds me of some chess endgame positions where a king must maintain the opposition from a distance.
1 Nov 2011
At first glance, I believe that would be the only winning move in standard EWN, too, for slightly different but related reasons.
1 Nov 2011
No, in standard EWN this position is lost for the first player.
If I made no mistake this is the only symmetrical position which is lost in a two-stone-endgame.
2 Nov 2011
> No, in standard EWN this position is lost for the first player.
> If I made no mistake this is the only symmetrical position
> which is lost in a two-stone-endgame.
The father of sybil_c should be able to shed more light on this.
He seems to have complete Ewn databases for all positions with up
to seven stones.
Sybil_Dad, can you hear us???
Ingo.
2 Nov 2011
I agree with Hanfried. All the other symmetric positions are a win for the player to move. By my quick calculation, there aren't any symmetric 4-stone positions in which the player to move is dead-lost, but there are several in which the player to move is clearly worse. What's interesting is how similar the very worst such 4-stone position looks to the lost 2-stone position.</ br>
<br/>A - - - -
<br/>- - - - -
<br/>6 - - - -
<br/>- - - - -
<br/>- - F - 1
<br/>
The player to move should lose this position just over 5/6 of the time.
2 Nov 2011
Ahh... I should spend more time thinking before I post. Hanfried seems to have considered only rotational symmetry, and I'd only considered mirrored. Turns out there's one (after collapsing symmetry along the diagonal) lost to-move 2-stone position from each:
<br/>- - - - - - A - - -
<br/>A - - - - - - - - -
<br/>- - - - - - - - - -
<br/>- - - - - - - - - -
<br/>- - - 1 - - - - 1 -
<br/>