What is the only winning move for Blue here?

game 1370283, after Red played 114

Nice position.

Only Northwards!

That is cute. It reminds me of some chess endgame positions where a king must maintain the opposition from a distance.

At first glance, I believe that would be the only winning move in standard EWN, too, for slightly different but related reasons.

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.

> 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.

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.

A - - - -
- - - - -
6 - - - -
- - - - -
- - F - 1

The player to move should lose this position just over 5/6 of the time.

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:

- - - - -   - A - - -
A - - - -   - - - - -
- - - - -   - - - - -
- - - - -   - - - - -
- - - 1 -   - - - 1 -