Tsume Othello #5622222 (empty 12)
To move: Black — find the best move
a
b
c
d
e
f
g
h
1
2
3
4
5
6
7
8
26 26
Why this move works
The answer is c2. Reading to the end, this move maximizes your final disc count (final +6, 4 discs better than the next-best).
The move that flips the most right now is a5 (5 discs), but it is not best. The final margin is only +6 — in the endgame a single move decides the result.