NONE!!! Or are you assuming perfect play?
Coconuts: 22 with 4x symmetry. We know because only one white stone sits on the board after five moves that was captured, limiting to the corner and the side. Because we know which move is, it can't be a move to capture, but a move where the white stone was. So that puts us in the corner. Now, can go wherever we want it to, so there are 22 different board points (25 points - 3 taken up) for it. There are four corners and we can move the position into any of them, so we end up with: 22 x 4 = 88. I think that's right!
ferdi: Not bad, but there are some more :-)
unkx80: In this position, given that one White stone must be captured at a, is the only legal move for . After accounting for symmetry, there are 8 such positions.