1 files changed, 22 insertions, 9 deletions
diff --git a/src/generate.c b/src/generate.c
index 7362fba..3e3c3a5 100755
--- a/src/generate.c
+++ b/src/generate.c
@@ -2467,20 +2467,33 @@ Return value:
     //
 
     //
-    // Pre-populate killer/bonuses.  (Tried Crafty-style ordering here
-    // -- both of this ply's own killers before either ply-2-back one
-    // -- measured worse EBF on ecm_quick than this interleaved order.
-    // Back to interleaved as the known-good baseline.)
+    // Pre-populate killer/bonuses.  Crafty-style ordering: both of this
+    // ply's own killers before either ply-2-back one.  (Reverted twice
+    // before -- see git history -- but this pass is on top of both
+    // NumLeftoverMovesToSelect and the mvNullmoveQuietRefutations fix
+    // (dynamic.c/searchsup.c), and beats the interleaved order (this
+    // ply's killer1, ply-2's killer1, this ply's killer2, ply-2's
+    // killer2) head-to-head on every metric with the fix applied to
+    // both: more solves, fewer nodes, equal-or-higher first-move beta
+    // cutoff on 2 of 3 curated suites. Both orderings lose first-move
+    // cutoff rate vs. head_reference once the backfill is added -- that
+    // appears to be a cost of the backfill itself, not of tier order --
+    // but Crafty order is the one where the backfilled data lands in a
+    // tier (this ply's own killer[1], promoted to SECOND_KILLER here)
+    // that's otherwise structurally almost always empty, so it's pure
+    // upside there; under interleaved order the same backfill instead
+    // lands in THIRD_KILLER, behind two already-real proven killers,
+    // where it appears to cost more (misordering) than it gives.)
     //
     sKillers[0].mv = ctx->mvKiller[uPly][0];
     sKillers[0].uBonus = FIRST_KILLER;
-    sKillers[1].mv.uMove = sKillers[3].mv.uMove = 0;
-    sKillers[2].mv = ctx->mvKiller[uPly][1];
-    sKillers[2].uBonus = THIRD_KILLER;
+    sKillers[1].mv = ctx->mvKiller[uPly][1];
+    sKillers[1].uBonus = SECOND_KILLER;
+    sKillers[2].mv.uMove = sKillers[3].mv.uMove = 0;
     if (uPly > 1)
     {
-        sKillers[1].mv = ctx->mvKiller[uPly - 2][0];
-        sKillers[1].uBonus = SECOND_KILLER;
+        sKillers[2].mv = ctx->mvKiller[uPly - 2][0];
+        sKillers[2].uBonus = THIRD_KILLER;
         sKillers[3].mv = ctx->mvKiller[uPly - 2][1];
         sKillers[3].uBonus = FOURTH_KILLER;
     }