Penalty for isolated shogi pawns

shogi
ELO: 6.95 +-33.2 (95%) LOS: 66.0%
Total: 400 W: 193 L: 185 D: 22

euroshogi
ELO: 20.87 +-33.1 (95%) LOS: 89.3%
Total: 400 W: 200 L: 176 D: 24

minishogi
ELO: 26.11 +-32.9 (95%) LOS: 94.1%
Total: 400 W: 200 L: 170 D: 30

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 805c816..2ce62e8 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -166,6 +166,9 @@ namespace {
 
         if (phalanx)
             score += Connected[opposed][bool(phalanx)][0][relative_rank(Us, s, pos.max_rank())] / 2;
+
+        else if (!neighbours)
+            score -= Isolated / 2;
     }
 
     return score;