diff --git a/cpp/src/board.cpp b/cpp/src/board.cpp
index 6e65fd1..b8c1f43 100644
--- a/cpp/src/board.cpp
+++ b/cpp/src/board.cpp
@@ -183,7 +183,8 @@ Board Board::make_move(Move move) const {
 
     // -- Handle en passant target being eaten
     if (move.en_passant)
-        ret.squares[move.target_square - 8] = Piece::None;
+        ret.squares[move.target_square + (white_to_play ? -8 : 8)] =
+            Piece::None;
 
     // -- Handle promotion
     if (move.promoting_to != Piece::None)