template<Tracing T>  template<Color Us, PieceType Pt>
  Score Evaluation<T>::evaluate_pieces() {

    const Color Them = (Us == WHITE ? BLACK : WHITE);
    const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
                                               : Rank5BB | Rank4BB | Rank3BB);
    const Square* pl = pos.squares<Pt>(Us);

    Bitboard b, bb;
    Square s;
    Score score = SCORE_ZERO;

    attackedBy[Us][Pt] = 0;

    while ((s = *pl++) != SQ_NONE)
    {
        // Find attacked squares, including x-ray attacks for bishops and rooks
        b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
          : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
                         : pos.attacks_from<Pt>(s);

        if (pos.pinned_pieces(Us) & s)
            b &= LineBB[pos.square<KING>(Us)][s];

        attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
        attackedBy[Us][ALL_PIECES] |= attackedBy[Us][Pt] |= b;

        if (b & kingRing[Them])
        {
            kingAttackersCount[Us]++;
            kingAttackersWeight[Us] += KingAttackWeights[Pt];
            kingAdjacentZoneAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
        }

        int mob = popcount(b & mobilityArea[Us]);

        mobility[Us] += MobilityBonus[Pt - 2][mob];

        // Bonus for this piece as a king protector
        score += KingProtector[Pt - 2] * distance(s, pos.square<KING>(Us));

        if (Pt == BISHOP || Pt == KNIGHT)
        {
            // Bonus for outpost squares
            bb = OutpostRanks & ~pe->pawn_attacks_span(Them);
            if (bb & s)
                score += Outpost[Pt == BISHOP][!!(attackedBy[Us][PAWN] & s)] * 2;
            else
            {
                bb &= b & ~pos.pieces(Us);
                if (bb)
                   score += Outpost[Pt == BISHOP][!!(attackedBy[Us][PAWN] & bb)];
            }

            // Bonus when behind a pawn
            if (    relative_rank(Us, s) < RANK_5
                && (pos.pieces(PAWN) & (s + pawn_push(Us))))
                score += MinorBehindPawn;

            if (Pt == BISHOP)
            {
                // Penalty for pawns on the same color square as the bishop
                score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s);

                // Bonus for bishop on a long diagonal without pawns in the center
                if (    (LongDiagonals & s)
                    && !(attackedBy[Them][PAWN] & s)
                    && !(Center & PseudoAttacks[BISHOP][s] & pos.pieces(PAWN)))
                    score += LongRangedBishop;
            }

            // An important Chess960 pattern: A cornered bishop blocked by a friendly
            // pawn diagonally in front of it is a very serious problem, especially
            // when that pawn is also blocked.
            if (   Pt == BISHOP
                && pos.is_chess960()
                && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
            {
                Square d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
                if (pos.piece_on(s + d) == make_piece(Us, PAWN))
                    score -= !pos.empty(s + d + pawn_push(Us))                ? TrappedBishopA1H1 * 4
                            : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
                                                                              : TrappedBishopA1H1;
            }
        }

        if (Pt == ROOK)
        {
            // Bonus for aligning with enemy pawns on the same rank/file
            if (relative_rank(Us, s) >= RANK_5)
                score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);

            // Bonus when on an open or semi-open file
            if (pe->semiopen_file(Us, file_of(s)))
                score += RookOnFile[!!pe->semiopen_file(Them, file_of(s))];

            // Penalty when trapped by the king, even more if the king cannot castle
            else if (mob <= 3)
            {
                Square ksq = pos.square<KING>(Us);

                if (   ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
                    && !pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
                    score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
            }
        }

        if (Pt == QUEEN)
        {
            // Penalty if any relative pin or discovered attack against the queen
            Bitboard pinners;
            if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, pinners))
                score -= WeakQueen;
        }
    }

    if (T)
        Trace::add(Pt, Us, score);

    return score;
  }

// evaluate_king() assigns bonuses and penalties to a king of a given color

  template<Tracing T>  template<Color Us>
  Score Evaluation<T>::evaluate_king() {

    const Color Them    = (Us == WHITE ? BLACK : WHITE);
    const Square Up     = (Us == WHITE ? NORTH : SOUTH);
    const Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
                                       : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);

    const Square ksq = pos.square<KING>(Us);
    Bitboard kingOnlyDefended, undefended, b, b1, b2, safe, other;
    int kingDanger;

    // King shelter and enemy pawns storm
    Score score = pe->king_safety<Us>(pos, ksq);

    // Main king safety evaluation
    if (kingAttackersCount[Them] > (1 - pos.count<QUEEN>(Them)))
    {
        // Find the attacked squares which are defended only by our king...
        kingOnlyDefended =   attackedBy[Them][ALL_PIECES]
                          &  attackedBy[Us][KING]
                          & ~attackedBy2[Us];

        // ... and those which are not defended at all in the larger king ring
        undefended =   attackedBy[Them][ALL_PIECES]
                    & ~attackedBy[Us][ALL_PIECES]
                    &  kingRing[Us]
                    & ~pos.pieces(Them);

        // Initialize the 'kingDanger' variable, which will be transformed
        // later into a king danger score. The initial value is based on the
        // number and types of the enemy's attacking pieces, the number of
        // attacked and weak squares around our king, the absence of queen and
        // the quality of the pawn shelter (current 'score' value).
        kingDanger =        kingAttackersCount[Them] * kingAttackersWeight[Them]
                    + 102 * kingAdjacentZoneAttacksCount[Them]
                    + 191 * popcount(kingOnlyDefended | undefended)
                    + 143 * !!pos.pinned_pieces(Us)
                    - 848 * !pos.count<QUEEN>(Them)
                    -   9 * mg_value(score) / 8
                    +  40;

        // Analyse the safe enemy's checks which are possible on next move
        safe  = ~pos.pieces(Them);
        safe &= ~attackedBy[Us][ALL_PIECES] | (kingOnlyDefended & attackedBy2[Them]);

        b1 = pos.attacks_from<  ROOK>(ksq);
        b2 = pos.attacks_from<BISHOP>(ksq);

        // Enemy queen safe checks
        if ((b1 | b2) & attackedBy[Them][QUEEN] & safe)
            kingDanger += QueenCheck;

        // For minors and rooks, also consider the square safe if attacked twice,
        // and only defended by our queen.
        safe |=  attackedBy2[Them]
               & ~(attackedBy2[Us] | pos.pieces(Them))
               & attackedBy[Us][QUEEN];

        // Some other potential checks are also analysed, even from squares
        // currently occupied by the opponent own pieces, as long as the square
        // is not attacked by our pawns, and is not occupied by a blocked pawn.
        other = ~(   attackedBy[Us][PAWN]
                  | (pos.pieces(Them, PAWN) & shift<Up>(pos.pieces(PAWN))));

        // Enemy rooks safe and other checks
        if (b1 & attackedBy[Them][ROOK] & safe)
            kingDanger += RookCheck;

        else if (b1 & attackedBy[Them][ROOK] & other)
            score -= OtherCheck;

        // Enemy bishops safe and other checks
        if (b2 & attackedBy[Them][BISHOP] & safe)
            kingDanger += BishopCheck;

        else if (b2 & attackedBy[Them][BISHOP] & other)
            score -= OtherCheck;

        // Enemy knights safe and other checks
        b = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
        if (b & safe)
            kingDanger += KnightCheck;

        else if (b & other)
            score -= OtherCheck;

        // Transform the kingDanger units into a Score, and substract it from the evaluation
        if (kingDanger > 0)
            score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
    }

    // King tropism: firstly, find squares that opponent attacks in our king flank
    File kf = file_of(ksq);
    b = attackedBy[Them][ALL_PIECES] & KingFlank[kf] & Camp;

    assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0);
    assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b));

    // Secondly, add the squares which are attacked twice in that flank and
    // which are not defended by our pawns.
    b =  (Us == WHITE ? b << 4 : b >> 4)
       | (b & attackedBy2[Them] & ~attackedBy[Us][PAWN]);

    score -= CloseEnemies * popcount(b);

    // Penalty when our king is on a pawnless flank
    if (!(pos.pieces(PAWN) & KingFlank[kf]))
        score -= PawnlessFlank;

    if (T)
        Trace::add(KING, Us, score);

    return score;
  }

// evaluate_threats() assigns bonuses according to the types of the attacking
  // and the attacked pieces.

  template<Tracing T>  template<Color Us>
  Score Evaluation<T>::evaluate_threats() {

    const Color Them        = (Us == WHITE ? BLACK      : WHITE);
    const Square Up         = (Us == WHITE ? NORTH      : SOUTH);
    const Square Left       = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
    const Square Right      = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
    const Bitboard TRank3BB = (Us == WHITE ? Rank3BB    : Rank6BB);

    Bitboard b, weak, defended, stronglyProtected, safeThreats;
    Score score = SCORE_ZERO;

    // Non-pawn enemies attacked by a pawn
    weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & attackedBy[Us][PAWN];

    if (weak)
    {
        b = pos.pieces(Us, PAWN) & ( ~attackedBy[Them][ALL_PIECES]
                                    | attackedBy[Us][ALL_PIECES]);

        safeThreats = (shift<Right>(b) | shift<Left>(b)) & weak;

        score += ThreatBySafePawn * popcount(safeThreats);

        if (weak ^ safeThreats)
            score += ThreatByHangingPawn;
    }

    // Squares strongly protected by the opponent, either because they attack the
    // square with a pawn, or because they attack the square twice and we don't.
    stronglyProtected =  attackedBy[Them][PAWN]
                       | (attackedBy2[Them] & ~attackedBy2[Us]);

    // Non-pawn enemies, strongly protected
    defended =  (pos.pieces(Them) ^ pos.pieces(Them, PAWN))
              & stronglyProtected;

    // Enemies not strongly protected and under our attack
    weak =   pos.pieces(Them)
          & ~stronglyProtected
          &  attackedBy[Us][ALL_PIECES];

    // Add a bonus according to the kind of attacking pieces
    if (defended | weak)
    {
        b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
        while (b)
        {
            Square s = pop_lsb(&b);
            score += ThreatByMinor[type_of(pos.piece_on(s))];
            if (type_of(pos.piece_on(s)) != PAWN)
                score += ThreatByRank * (int)relative_rank(Them, s);
        }

        b = (pos.pieces(Them, QUEEN) | weak) & attackedBy[Us][ROOK];
        while (b)
        {
            Square s = pop_lsb(&b);
            score += ThreatByRook[type_of(pos.piece_on(s))];
            if (type_of(pos.piece_on(s)) != PAWN)
                score += ThreatByRank * (int)relative_rank(Them, s);
        }

        score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);

        b = weak & attackedBy[Us][KING];
        if (b)
            score += ThreatByKing[more_than_one(b)];
    }

    // Bonus for opponent unopposed weak pawns
    if (pos.pieces(Us, ROOK, QUEEN))
        score += WeakUnopposedPawn * pe->weak_unopposed(Them);

    // Find squares where our pawns can push on the next move
    b  = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
    b |= shift<Up>(b & TRank3BB) & ~pos.pieces();

    // Keep only the squares which are not completely unsafe
    b &= ~attackedBy[Them][PAWN]
        & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);

    // Add a bonus for each new pawn threats from those squares
    b =  (shift<Left>(b) | shift<Right>(b))
       &  pos.pieces(Them)
       & ~attackedBy[Us][PAWN];

    score += ThreatByPawnPush * popcount(b);

    if (T)
        Trace::add(THREAT, Us, score);

    return score;
  }

// evaluate_passed_pawns() evaluates the passed pawns and candidate passed
  // pawns of the given color.

  template<Tracing T>  template<Color Us>
  Score Evaluation<T>::evaluate_passed_pawns() {

    const Color Them = (Us == WHITE ? BLACK : WHITE);
    const Square Up  = (Us == WHITE ? NORTH : SOUTH);

    Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares;
    Score score = SCORE_ZERO;

    b = pe->passed_pawns(Us);

    while (b)
    {
        Square s = pop_lsb(&b);

        assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));

        bb = forward_file_bb(Us, s) & (attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
        score -= HinderPassedPawn * popcount(bb);

        int r = relative_rank(Us, s) - RANK_2;
        int rr = r * (r - 1);

        Value mbonus = Passed[MG][r], ebonus = Passed[EG][r];

        if (rr)
        {
            Square blockSq = s + Up;

            // Adjust bonus based on the king's proximity
            ebonus +=  distance(pos.square<KING>(Them), blockSq) * 5 * rr
                     - distance(pos.square<KING>(  Us), blockSq) * 2 * rr;

            // If blockSq is not the queening square then consider also a second push
            if (relative_rank(Us, blockSq) != RANK_8)
                ebonus -= distance(pos.square<KING>(Us), blockSq + Up) * rr;

            // If the pawn is free to advance, then increase the bonus
            if (pos.empty(blockSq))
            {
                // If there is a rook or queen attacking/defending the pawn from behind,
                // consider all the squaresToQueen. Otherwise consider only the squares
                // in the pawn's path attacked or occupied by the enemy.
                defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s);

                bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);

                if (!(pos.pieces(Us) & bb))
                    defendedSquares &= attackedBy[Us][ALL_PIECES];

                if (!(pos.pieces(Them) & bb))
                    unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them);

                // If there aren't any enemy attacks, assign a big bonus. Otherwise
                // assign a smaller bonus if the block square isn't attacked.
                int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;

                // If the path to the queen is fully defended, assign a big bonus.
                // Otherwise assign a smaller bonus if the block square is defended.
                if (defendedSquares == squaresToQueen)
                    k += 6;

                else if (defendedSquares & blockSq)
                    k += 4;

                mbonus += k * rr, ebonus += k * rr;
            }
            else if (pos.pieces(Us) & blockSq)
                mbonus += rr + r * 2, ebonus += rr + r * 2;
        } // rr != 0

        // Scale down bonus for candidate passers which need more than one
        // pawn push to become passed or have a pawn in front of them.
        if (!pos.pawn_passed(Us, s + Up) || (pos.pieces(PAWN) & forward_file_bb(Us, s)))
            mbonus /= 2, ebonus /= 2;

        score += make_score(mbonus, ebonus) + PassedFile[file_of(s)];
    }

    if (T)
        Trace::add(PASSED, Us, score);

    return score;
  }