diff --git a/src/nnue/features/half_ka_v2_hm.cpp b/src/nnue/features/half_ka_v2_hm.cpp
index 70e9beeb1..5bcfb0849 100644
--- a/src/nnue/features/half_ka_v2_hm.cpp
+++ b/src/nnue/features/half_ka_v2_hm.cpp
@@ -29,9 +29,10 @@ namespace Stockfish::Eval::NNUE::Features {
 
 // Index of a feature for a given king position and another piece on some square
 template<Color Perspective>
-inline IndexType HalfKAv2_hm::make_index(Square s, Piece pc, Square ksq) {
-    return IndexType((int(s) ^ OrientTBL[Perspective][ksq]) + PieceSquareIndex[Perspective][pc]
-                     + KingBuckets[Perspective][ksq]);
+IndexType HalfKAv2_hm::make_index(Square s, Piece pc, Square ksq) {
+    const IndexType flip = 56 * Perspective;
+    return (IndexType(s) ^ OrientTBL[ksq] ^ flip) + PieceSquareIndex[Perspective][pc]
+         + KingBuckets[int(ksq) ^ flip];
 }
 
 // Get a list of indices for active features
diff --git a/src/nnue/features/half_ka_v2_hm.h b/src/nnue/features/half_ka_v2_hm.h
index ba122adc8..b72bbbce4 100644
--- a/src/nnue/features/half_ka_v2_hm.h
+++ b/src/nnue/features/half_ka_v2_hm.h
@@ -75,45 +75,29 @@ class HalfKAv2_hm {
 
 #define B(v) (v * PS_NB)
     // clang-format off
-    static constexpr int KingBuckets[COLOR_NB][SQUARE_NB] = {
-      { B(28), B(29), B(30), B(31), B(31), B(30), B(29), B(28),
+    static constexpr IndexType KingBuckets[SQUARE_NB] = {
+        B(28), B(29), B(30), B(31), B(31), B(30), B(29), B(28),
         B(24), B(25), B(26), B(27), B(27), B(26), B(25), B(24),
         B(20), B(21), B(22), B(23), B(23), B(22), B(21), B(20),
         B(16), B(17), B(18), B(19), B(19), B(18), B(17), B(16),
         B(12), B(13), B(14), B(15), B(15), B(14), B(13), B(12),
         B( 8), B( 9), B(10), B(11), B(11), B(10), B( 9), B( 8),
         B( 4), B( 5), B( 6), B( 7), B( 7), B( 6), B( 5), B( 4),
-        B( 0), B( 1), B( 2), B( 3), B( 3), B( 2), B( 1), B( 0) },
-      { B( 0), B( 1), B( 2), B( 3), B( 3), B( 2), B( 1), B( 0),
-        B( 4), B( 5), B( 6), B( 7), B( 7), B( 6), B( 5), B( 4),
-        B( 8), B( 9), B(10), B(11), B(11), B(10), B( 9), B( 8),
-        B(12), B(13), B(14), B(15), B(15), B(14), B(13), B(12),
-        B(16), B(17), B(18), B(19), B(19), B(18), B(17), B(16),
-        B(20), B(21), B(22), B(23), B(23), B(22), B(21), B(20),
-        B(24), B(25), B(26), B(27), B(27), B(26), B(25), B(24),
-        B(28), B(29), B(30), B(31), B(31), B(30), B(29), B(28) }
+        B( 0), B( 1), B( 2), B( 3), B( 3), B( 2), B( 1), B( 0),
     };
     // clang-format on
 #undef B
     // clang-format off
     // Orient a square according to perspective (rotates by 180 for black)
-    static constexpr int OrientTBL[COLOR_NB][SQUARE_NB] = {
-      { SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
+    static constexpr IndexType OrientTBL[SQUARE_NB] = {
         SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
         SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
         SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
         SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
         SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
         SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
-        SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1 },
-      { SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8,
-        SQ_H8, SQ_H8, SQ_H8, SQ_H8, SQ_A8, SQ_A8, SQ_A8, SQ_A8 }
+        SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1,
+        SQ_H1, SQ_H1, SQ_H1, SQ_H1, SQ_A1, SQ_A1, SQ_A1, SQ_A1 ,
     };
     // clang-format on