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

Book: 307 / 987

# move proof disproof
1 e5 5 307
2 d5 2 307
3 b5 144 308
4 g6 100 308
5 c5 75 308
6 c6 62 308
7 Nh6 60 308
8 h6 59 308
9 a6 57 308
10 g5 40 308
11 f5 21 308
12 h5 12 308
13 a5 23 309
14 Nf6 6 309
15 d6 4 309
16 Nc6 62 310
17 e6 26 313
18 b6 121 317
19 f6 51 319
20 Na6 57 326