Click on the third or sixth rank to set the en passant target square.

Book: ∞ / 0

# move proof disproof
1 a5 0
2 Kd6 0
3 Kd8 0
4 Kc7 0
5 Na6 0
6 a6 0
7 Ke6 0
8 Ba6 0
9 Bb7 0
10 c5 0
11 Ke8 0
12 Ke7 0