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

EGTB: win in 1 half-moves

# move score
1 B5xa4 win in 3 half-moves
2 Rxa4 win in 3 half-moves
3 B3xa4 loss in 4 half-moves
4 Bxe8 loss in 1 half-moves