The black pawn , which would have been able to capture the white pawn if the white one had moved forward only one square , can capture the white pawn in its next move - `` in passing '' as if the white pawn had moved forward only one square . That enemy pawn , which would have been able to capture the moving pawn had it advanced only one square , is entitled to capture the moving pawn `` in passing '' as if it had advanced only one square .