A1 opening

R5, C5, Va1

The a1 opening (in the acute corner) is one of only two openings known to be defeatedable. The other is b1.

(This does not mean that these are the worst possible opening moves. Compare with the diagrams on the openings page at the queenbee site)

Due to the symmetry of the Hex board, the same is true of the opposite hexes, but they are not usually referred to explicitly because their designation depends on the size of the board. References for proofs can be found on the Hex Theory page.