diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index e5e3cb6c..aeaa4336 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -475,6 +475,7 @@ namespace {
                      +  69 * kingAttacksCount[Them]
                      + 185 * popcount(kingRing[Us] & weak)
                      + 150 * popcount(pos.blockers_for_king(Us) | unsafeChecks)
+                     +       tropism * tropism / 4
                      - 873 * !pos.count<QUEEN>(Them)
                      -   6 * mg_value(score) / 8
                      +       mg_value(mobility[Them] - mobility[Us])