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

Book: 222 / 1177

# move proof disproof
1 e5 26 222
2 f5 11 222
3 d5 2 222
4 b5 572 223
5 g6 120 223
6 b6 52 223
7 f6 40 223
8 Na6 30 223
9 Nf6 28 223
10 e6 28 223
11 Nc6 34 225
12 a6 2 225
13 c6 21 226
14 h5 34 227
15 a5 2 227
16 g5 47 228
17 h6 60 230
18 Nh6 45 236
19 d6 23 238
20 c5 0 ∞