diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index e706a88c26..9a86aafa21 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -176,6 +176,11 @@ bool render
         /// </summary>
         public event EventHandler<TipChangedEventArgs> TipChanged;
 
+        /// <summary>
+        /// An event which is invoked when <see cref="Tip"/> is changed.
+        /// </summary>
+        public event EventHandler<OnReorgEventArgs> OnReorg;
+
         public IBlockPolicy<T> Policy { get; }
 
         /// <summary>
@@ -1293,6 +1298,7 @@ IEnumerable<TxId> GetTxIdsWithRange(BlockChain<T> chain, Block<T> start, Block<T
                 Store.SetCanonicalChainId(Id);
                 _blocks = new BlockSet<T>(Store);
                 TipChanged?.Invoke(this, tipChangedEventArgs);
+                OnReorg?.Invoke(this, new OnReorgEventArgs());
                 _transactions = new TransactionSet<T>(Store);
                 Store.DeleteChainId(obsoleteId);
             }
@@ -1567,5 +1573,12 @@ public class TipChangedEventArgs : EventArgs
             /// </summary>
             public HashDigest<SHA256> Hash { get; set; }
         }
+
+        /// <summary>
+        /// Provides data for the <see cref="TipChanged"/> event.
+        /// </summary>
+        public class OnReorgEventArgs : EventArgs
+        {
+        }
     }
 }