From f6bdc83c4bc83d26420d148ea09f7a162d7563d8 Mon Sep 17 00:00:00 2001
From: Alayan <alayan.feh@gmail.com>
Date: Tue, 1 Jan 2019 14:43:22 +0100
Subject: [PATCH] Bonus for passed pawns much more advanced than enemy passed
 pawns

---
 src/evaluate.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 53a54006a7a..bb17acb0cbd 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -161,6 +161,7 @@ namespace {
   constexpr Score LongDiagonalBishop = S( 45,  0);
   constexpr Score MinorBehindPawn    = S( 18,  3);
   constexpr Score PawnlessFlank      = S( 17, 95);
+  constexpr Score PawnTempo          = S(  0,  4);
   constexpr Score RestrictedPiece    = S(  7,  7);
   constexpr Score RookOnPawn         = S( 10, 32);
   constexpr Score SliderOnQueen      = S( 59, 18);
@@ -669,6 +670,12 @@ namespace {
                     k += 4;
 
                 bonus += make_score(k * w, k * w);
+
+                int rt = pe->passed_pawns(Them) ? relative_rank(Them, frontmost_sq(Them, pe->passed_pawns(Them)))
+                                                : RANK_1;
+                if (   (defendedSquares == squaresToQueen)
+                    && (r >  rt)                          )
+                    bonus += PawnTempo*w;
             }
         } // rank > RANK_3