diff --git a/src/Makefile.am b/src/Makefile.am
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -116,6 +116,7 @@
   core_io.h \
   core_memusage.h \
   cuckoocache.h \
+  diskblockindex.h \
   diskblockpos.h \
   dstencode.h \
   fs.h \
diff --git a/src/blockindex.h b/src/blockindex.h
--- a/src/blockindex.h
+++ b/src/blockindex.h
@@ -220,4 +220,3 @@
 };
 
 #endif // BITCOIN_BLOCKINDEX_H
-
diff --git a/src/chain.h b/src/chain.h
--- a/src/chain.h
+++ b/src/chain.h
@@ -61,68 +61,6 @@
 const CBlockIndex *LastCommonAncestor(const CBlockIndex *pa,
                                       const CBlockIndex *pb);
 
-/** Used to marshal pointers into hashes for db storage. */
-class CDiskBlockIndex : public CBlockIndex {
-public:
-    uint256 hashPrev;
-
-    CDiskBlockIndex() { hashPrev = uint256(); }
-
-    explicit CDiskBlockIndex(const CBlockIndex *pindex) : CBlockIndex(*pindex) {
-        hashPrev = (pprev ? pprev->GetBlockHash() : uint256());
-    }
-
-    ADD_SERIALIZE_METHODS;
-
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream &s, Operation ser_action) {
-        int nVersion = s.GetVersion();
-        if (!(s.GetType() & SER_GETHASH)) {
-            READWRITE(VARINT(nVersion));
-        }
-
-        READWRITE(VARINT(nHeight));
-        READWRITE(nStatus);
-        READWRITE(VARINT(nTx));
-        if (nStatus.hasData() || nStatus.hasUndo()) {
-            READWRITE(VARINT(nFile));
-        }
-        if (nStatus.hasData()) {
-            READWRITE(VARINT(nDataPos));
-        }
-        if (nStatus.hasUndo()) {
-            READWRITE(VARINT(nUndoPos));
-        }
-
-        // block header
-        READWRITE(this->nVersion);
-        READWRITE(hashPrev);
-        READWRITE(hashMerkleRoot);
-        READWRITE(nTime);
-        READWRITE(nBits);
-        READWRITE(nNonce);
-    }
-
-    uint256 GetBlockHash() const {
-        CBlockHeader block;
-        block.nVersion = nVersion;
-        block.hashPrevBlock = hashPrev;
-        block.hashMerkleRoot = hashMerkleRoot;
-        block.nTime = nTime;
-        block.nBits = nBits;
-        block.nNonce = nNonce;
-        return block.GetHash();
-    }
-
-    std::string ToString() const {
-        std::string str = "CDiskBlockIndex(";
-        str += CBlockIndex::ToString();
-        str += strprintf("\n                hashBlock=%s, hashPrev=%s)",
-                         GetBlockHash().ToString(), hashPrev.ToString());
-        return str;
-    }
-};
-
 /**
  * An in-memory indexed chain of blocks.
  */
diff --git a/src/diskblockindex.h b/src/diskblockindex.h
new file mode 100644
--- /dev/null
+++ b/src/diskblockindex.h
@@ -0,0 +1,77 @@
+// Copyright (c) 2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_DISKBLOCKINDEX_H
+#define BITCOIN_DISKBLOCKINDEX_H
+
+#include "blockindex.h"
+#include "serialize.h"
+#include "tinyformat.h"
+#include "uint256.h"
+
+class CBlockIndex;
+
+/** Used to marshal pointers into hashes for db storage. */
+class CDiskBlockIndex : public CBlockIndex {
+public:
+    uint256 hashPrev;
+
+    CDiskBlockIndex() { hashPrev = uint256(); }
+
+    explicit CDiskBlockIndex(const CBlockIndex *pindex) : CBlockIndex(*pindex) {
+        hashPrev = (pprev ? pprev->GetBlockHash() : uint256());
+    }
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream &s, Operation ser_action) {
+        int nVersion = s.GetVersion();
+        if (!(s.GetType() & SER_GETHASH)) {
+            READWRITE(VARINT(nVersion));
+        }   
+
+        READWRITE(VARINT(nHeight));
+        READWRITE(nStatus);
+        READWRITE(VARINT(nTx));
+        if (nStatus.hasData() || nStatus.hasUndo()) {
+            READWRITE(VARINT(nFile));
+        }   
+        if (nStatus.hasData()) {
+            READWRITE(VARINT(nDataPos));
+        }   
+        if (nStatus.hasUndo()) {
+            READWRITE(VARINT(nUndoPos));
+        }   
+
+        // block header
+        READWRITE(this->nVersion);
+        READWRITE(hashPrev);
+        READWRITE(hashMerkleRoot);
+        READWRITE(nTime);
+        READWRITE(nBits);
+        READWRITE(nNonce);
+    }
+
+    uint256 GetBlockHash() const {
+        CBlockHeader block;
+        block.nVersion = nVersion;
+        block.hashPrevBlock = hashPrev;
+        block.hashMerkleRoot = hashMerkleRoot;
+        block.nTime = nTime;
+        block.nBits = nBits;
+        block.nNonce = nNonce;
+        return block.GetHash();
+    }
+
+    std::string ToString() const {
+        std::string str = "CDiskBlockIndex(";
+        str += CBlockIndex::ToString();
+        str += strprintf("\n                hashBlock=%s, hashPrev=%s)",
+                         GetBlockHash().ToString(), hashPrev.ToString());
+        return str;
+    }
+};
+
+#endif // BITCOIN_DISKBLOCKINDEX_H
diff --git a/src/test/test_bitcoin_fuzzy.cpp b/src/test/test_bitcoin_fuzzy.cpp
--- a/src/test/test_bitcoin_fuzzy.cpp
+++ b/src/test/test_bitcoin_fuzzy.cpp
@@ -7,10 +7,10 @@
 #endif
 
 #include "addrman.h"
-#include "chain.h"
 #include "coins.h"
 #include "compressor.h"
 #include "consensus/merkle.h"
+#include "diskblockindex.h"
 #include "net.h"
 #include "primitives/block.h"
 #include "protocol.h"
diff --git a/src/txdb.cpp b/src/txdb.cpp
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -7,6 +7,7 @@
 
 #include "chain.h"
 #include "chainparams.h"
+#include "diskblockindex.h"
 #include "hash.h"
 #include "init.h"
 #include "pow.h"