+ // Strength of pawn shelter for our king by [distance from edge][rank].
+ // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
+ constexpr Value ShelterStrength[int(FILE_NB) / 2][RANK_NB] = {
+ { V( -9), V(64), V(77), V( 44), V( 4), V( -1), V(-11) },
+ { V(-15), V(83), V(51), V(-10), V( 1), V(-10), V(-28) },
+ { V(-18), V(84), V(27), V(-12), V(21), V( -7), V(-36) },
+ { V( 12), V(79), V(25), V( 19), V( 9), V( -6), V(-33) }
+ };
+
+ // Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
+ // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
+ // no pawn on the given file, or their pawn is behind our king.
+ constexpr Value StormDanger[][4][RANK_NB] = {
+ { { V( 0), V(-290), V(-274), V(57), V(41) }, // BlockedByKing
+ { V( 0), V( 60), V( 144), V(39), V(13) },
+ { V( 0), V( 65), V( 141), V(41), V(34) },
+ { V( 0), V( 53), V( 127), V(56), V(14) } },
+ { { V( 4), V( 73), V( 132), V(46), V(31) }, // Unopposed
+ { V( 1), V( 64), V( 143), V(26), V(13) },
+ { V( 1), V( 47), V( 110), V(44), V(24) },
+ { V( 0), V( 72), V( 127), V(50), V(31) } },
+ { { V( 0), V( 0), V( 19), V(23), V( 1) }, // BlockedByPawn
+ { V( 0), V( 0), V( 88), V(27), V( 2) },
+ { V( 0), V( 0), V( 101), V(16), V( 1) },
+ { V( 0), V( 0), V( 111), V(22), V(15) } },
+ { { V(22), V( 45), V( 104), V(62), V( 6) }, // Unblocked
+ { V(31), V( 30), V( 99), V(39), V(19) },
+ { V(23), V( 29), V( 96), V(41), V(15) },
+ { V(21), V( 23), V( 116), V(41), V(15) } }
+ };