Good question Mark- It is open to interpretation and could go either way, but my sense is that it makes it a fairer game to allow it to capture. The way that I tend to look at it when in doubt is that the stone lands in the spot, creates a volatile situation which must be resolved by removing ALL affected pairs for both sides and then the game continues from the new position. So, for instance if one played into a spot which was a poof in two directions and would capture two pairs of the opponent's stones and create a five in a row the net result is: the five exists for a brief moment, but not long enough to win (it must still exist when it is the opponents turn to move), you capture two pairs while losing 3 stones (one in each direction in which a poof is formed + the one you placed to make the 5). It is now the opponent's turn. Any luck with my puzzle?