#1 · David J Bush
14 Oct 2019
This is based on two posts lazy made.
1. lguser, the swap can be generalized in a way that I’ve discovered several years ago. First player chooses a number N0 and places N0 stones of any color, second player chooses if he wants to play black or white or if he wants to choose another number N1 such that N1 and to place N1 stones and then first player has to choose and the process repeats with N2, N3, etc etc.
This should be the optimal swap rule, making the full use of the possibilities of the whole board.
2. David, It’s mother of all kludge because, depending on what you want, it can gives birth to different babies! You say chess960 has 480 distinct starts? In my game, there are ~2^128 distinct starts for 9x9 and ~2^191 for 11x11! And the branching factor remains almost as high for the next moves unless both players agree on a starting position and they start playing conventional hex from there. So you’ve plenty of choices, indeed, you’ve ALL the choices possible while ensuring termination! :)
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So, nothing is to prevent the first player from choosing N0=1 which is the pie rule as we play it. I suppose a white stone could be played under your rules, producing a position with white to move, but that would be silly.
In general, the more stones are on the board, the simpler the position is. I cannot conceive of any position created by the first player in which it would be desirable, from the second player's point of view, to add more stones to the board and hand the swap choice over to the opponent, instead of making the swap choice their self.
The numbers you provide are upper limits, much larger than the the truly interesting initial positions which have not been considered when analyzing more complicated positions with fewer stones on the board. Keep in mind the branching factor drops significantly faster with each move in Hex than it usually does in chess.
Memorizing an opening repertoire for chess 960 seems to me very difficult but not impossible, and I believe the same is true for Hex, regardless of what sort of kludge we munge onto its face. Of course, a larger grid is likely a better way to go., up to a point.