diff --git a/src/tt.cpp b/src/tt.cpp
index 33768ca4..b8fe7567 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -43,14 +43,15 @@ void TTEntry::save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev)
 
   // Overwrite less valuable entries
   if (  (k >> 48) != key16
-      || d / ONE_PLY > depth8 - 4
+      || d / ONE_PLY + 10 > depth8
       || b == BOUND_EXACT)
   {
       key16     = (uint16_t)(k >> 48);
       value16   = (int16_t)v;
       eval16    = (int16_t)ev;
       genBound8 = (uint8_t)(TT.generation8 | uint8_t(pv) << 2 | b);
-      depth8    = (int8_t)(d / ONE_PLY);
+      assert((d - DEPTH_NONE) / ONE_PLY >= 0);
+      depth8    = (uint8_t)((d - DEPTH_NONE) / ONE_PLY);
   }
 }
 
diff --git a/src/tt.h b/src/tt.h
index fefc8e2c..3608b77c 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -40,7 +40,7 @@ struct TTEntry {
   Move  move()  const { return (Move )move16; }
   Value value() const { return (Value)value16; }
   Value eval()  const { return (Value)eval16; }
-  Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)); }
+  Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)) + DEPTH_NONE; }
   bool is_pv() const { return (bool)(genBound8 & 0x4); }
   Bound bound() const { return (Bound)(genBound8 & 0x3); }
   void save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev);
@@ -53,7 +53,7 @@ private:
   int16_t  value16;
   int16_t  eval16;
   uint8_t  genBound8;
-  int8_t   depth8;
+  uint8_t  depth8;
 };
 
 
diff --git a/src/types.h b/src/types.h
index 2e36279d..b0758f43 100644
--- a/src/types.h
+++ b/src/types.h
@@ -101,7 +101,7 @@ typedef uint64_t Key;
 typedef uint64_t Bitboard;
 
 constexpr int MAX_MOVES = 256;
-constexpr int MAX_PLY   = 128;
+constexpr int MAX_PLY   = 246;
 
 /// A move needs 16 bits to be stored
 ///