diff --git a/lib/chain/chaindb.js b/lib/chain/chaindb.js
index 18fcf299..c51c418f 100644
--- a/lib/chain/chaindb.js
+++ b/lib/chain/chaindb.js
@@ -23,6 +23,7 @@ var Coin = require('../primitives/coin');
 var TX = require('../primitives/tx');
 var Address = require('../primitives/address');
 var ChainEntry = require('./chainentry');
+var U32 = utils.U32;
 var DUMMY = new Buffer([0]);
 
 /*
@@ -1135,11 +1136,8 @@ ChainDB.prototype.save = co(function* save(entry, block, view) {
 
 ChainDB.prototype._save = co(function* save(entry, block, view) {
   var hash = block.hash();
-  var height = new Buffer(4);
 
-  height.writeUInt32LE(entry.height, 0, true);
-
-  this.put(layout.h(hash), height);
+  this.put(layout.h(hash), U32(entry.height));
   this.put(layout.e(hash), entry.toRaw());
 
   this.cacheHash.set(entry.hash, entry);
diff --git a/lib/utils/utils.js b/lib/utils/utils.js
index dd335fb8..b9390119 100644
--- a/lib/utils/utils.js
+++ b/lib/utils/utils.js
@@ -1927,6 +1927,18 @@ utils.VerifyResult = function VerifyResult() {
   this.score = 0;
 };
 
+/**
+ * Serialize number as a u32le.
+ * @param {Number} num
+ * @returns {Buffer}
+ */
+
+utils.U32 = function U32(num) {
+  var data = new Buffer(4);
+  data.writeUInt32LE(num, 0, true);
+  return data;
+};
+
 /**
  * Create a lazy loader.
  * @param {Function} require
diff --git a/lib/wallet/browser.js b/lib/wallet/browser.js
index bbd85fae..369821b6 100644
--- a/lib/wallet/browser.js
+++ b/lib/wallet/browser.js
@@ -45,8 +45,11 @@ layout.walletdb = {
     return [+key.slice(1, 11), key.slice(11)];
   },
   R: 'R',
-  b: function b(hash) {
-    return 'b' + hash;
+  b: function b(height) {
+    return 'b' + pad32(height);
+  },
+  bb: function bb(key) {
+    return +key.slice(1);
   },
   e: function e(hash) {
     return 'e' + hash;
diff --git a/lib/wallet/txdb.js b/lib/wallet/txdb.js
index 2aec72a1..b87ee3f7 100644
--- a/lib/wallet/txdb.js
+++ b/lib/wallet/txdb.js
@@ -455,23 +455,27 @@ TXDB.prototype.hasPath = function hasPath(output) {
  * @returns {Promise}
  */
 
-TXDB.prototype.resolve = co(function* add(tx) {
-  var hash, result;
+TXDB.prototype.resolve = co(function* resolve(tx, block) {
+  var orphan, hash, result;
 
-  if (!this.options.resolution)
-    return [tx];
+  if (!this.options.resolution) {
+    orphan = new ResolvedOrphan(tx, block);
+    return [orphan];
+  }
 
   hash = tx.hash('hex');
 
-  if (yield this.hasTX(hash))
-    return [tx];
+  if (yield this.hasTX(hash)) {
+    orphan = new ResolvedOrphan(tx, block);
+    return [orphan];
+  }
 
-  result = yield this.verifyInputs(tx);
+  result = yield this.verifyInputs(tx, block);
 
   if (!result)
     return [];
 
-  return yield this.resolveOutputs(tx);
+  return yield this.resolveOutputs(tx, block);
 });
 
 /**
@@ -481,7 +485,7 @@ TXDB.prototype.resolve = co(function* add(tx) {
  * @returns {Promise}
  */
 
-TXDB.prototype.verifyInputs = co(function* verifyInputs(tx) {
+TXDB.prototype.verifyInputs = co(function* verifyInputs(tx, block) {
   var hash = tx.hash('hex');
   var hasOrphans = false;
   var orphans = [];
@@ -573,7 +577,7 @@ TXDB.prototype.verifyInputs = co(function* verifyInputs(tx) {
     if (!this.count[hash])
       this.count[hash] = 0;
 
-    this.orphans[key].push(new Orphan(tx, i));
+    this.orphans[key].push(new Orphan(tx, i, block));
     this.count[hash]++;
     this.totalOrphans++;
 
@@ -595,7 +599,7 @@ TXDB.prototype.verifyInputs = co(function* verifyInputs(tx) {
  * @returns {Promise}
  */
 
-TXDB.prototype.resolveOutputs = co(function* resolveOutputs(tx, resolved) {
+TXDB.prototype.resolveOutputs = co(function* resolveOutputs(tx, block, resolved) {
   var hash = tx.hash('hex');
   var i, j, input, output, key;
   var orphans, orphan, coin, valid;
@@ -607,7 +611,7 @@ TXDB.prototype.resolveOutputs = co(function* resolveOutputs(tx, resolved) {
   // Necessary for the first resolved tx
   // as well as the recursive behavior
   // below.
-  resolved.push(tx);
+  resolved.push(new ResolvedOrphan(tx, block));
 
   for (i = 0; i < tx.outputs.length; i++) {
     output = tx.outputs[i];
@@ -647,7 +651,7 @@ TXDB.prototype.resolveOutputs = co(function* resolveOutputs(tx, resolved) {
       if (valid) {
         if (--this.count[orphan.hash] === 0) {
           delete this.count[orphan.hash];
-          yield this.resolveOutputs(orphan.tx, resolved);
+          yield this.resolveOutputs(orphan.tx, orphan.block, resolved);
         }
         break;
       }
@@ -897,8 +901,12 @@ TXDB.prototype._add = co(function* add(tx, block) {
 
   if (existing) {
     // Existing tx is already confirmed. Ignore.
-    if (existing.height !== -1)
+    if (existing.height !== -1) {
+      if (block) {
+        // XXX need to return true here, could be a rescan.
+      }
       return;
+    }
 
     // The incoming tx won't confirm the
     // existing one anyway. Ignore.
@@ -909,7 +917,7 @@ TXDB.prototype._add = co(function* add(tx, block) {
     tx.ps = existing.ps;
 
     // Confirm transaction.
-    return yield this.confirm(tx, block);
+    return yield this._confirm(tx, block);
   }
 
   if (tx.height === -1) {
@@ -1126,65 +1134,58 @@ TXDB.prototype.addTXRecord = co(function* addTXRecord(tx) {
   this.walletdb.writeTX(this.wallet, hash, wids);
 });
 
-TXDB.prototype.addBlockRecord = co(function* addBlockRecord(tx, record) {
-  var hash = tx.hash('hex');
-  var block = yield this.walletdb.getBlock(record.hash);
-
-  if (!block)
-    block = record.clone();
-
-  if (block.hashes.indexOf(hash) !== -1)
-    return;
-
-  block.hashes.push(hash);
-
-  this.walletdb.writeBlock(this.wallet, block);
-});
-
 TXDB.prototype.removeTXRecord = co(function* removeTXRecord(tx) {
   var hash = tx.hash('hex');
   var wids = yield this.walletdb.getWalletsByTX(hash);
   var result;
 
   if (!wids)
-    return true;
+    return;
 
   result = utils.binaryRemove(wids, this.wallet.wid, cmp);
 
   if (!result)
-    return false;
+    return;
 
-  if (wids.length > 0) {
-    this.walletdb.writeTX(this.wallet, hash, wids);
-    return false;
+  yield this.removeBlockRecord(tx, tx.height);
+
+  if (wids.length === 0) {
+    this.walletdb.unwriteTX(this.wallet, hash);
+    return;
   }
 
-  this.walletdb.removeTX(this.wallet, hash);
-
-  return true;
+  this.walletdb.writeTX(this.wallet, hash, wids);
 });
 
-TXDB.prototype.removeBlockRecord = co(function* removeBlockRecord(tx, blk) {
+TXDB.prototype.addBlockRecord = co(function* addBlockRecord(tx, record) {
   var hash = tx.hash('hex');
-  var block = yield this.walletdb.getBlock(blk);
-  var index;
+  var block = yield this.walletdb.getBlock(record.height);
+
+  if (!block)
+    block = record.clone();
+
+  if (!block.add(hash, this.wallet.wid))
+    return;
+
+  this.walletdb.writeBlock(this.wallet, block);
+});
+
+TXDB.prototype.removeBlockRecord = co(function* removeBlockRecord(tx, height) {
+  var hash = tx.hash('hex');
+  var block = yield this.walletdb.getBlock(height);
 
   if (!block)
     return;
 
-  index = block.hashes.indexOf(hash);
-
-  if (index === -1)
+  if (!block.remove(hash, this.wallet.wid))
     return;
 
-  block.hashes.splice(index, 1);
-
-  if (block.hashes.length > 0) {
-    this.walletdb.writeBlock(this.wallet, block);
+  if (block.txs.length === 0) {
+    this.walletdb.unwriteBlock(this.wallet, block);
     return;
   }
 
-  this.walletdb.removeBlock(this.wallet, block);
+  this.walletdb.writeBlock(this.wallet, block);
 });
 
 
@@ -1199,13 +1200,48 @@ function cmp(a, b) {
  * @returns {Promise}
  */
 
-TXDB.prototype.confirm = co(function* confirm(tx, block) {
+TXDB.prototype.confirm = co(function* confirm(hash, block) {
+  var tx = yield this.getTX(hash);
+  var details;
+
+  if (!tx)
+    return;
+
+  tx.height = block.height;
+  tx.block = block.hash;
+  tx.index = -1;
+  tx.ts = utils.now();
+
+  this.start();
+
+  try {
+    details = yield this._confirm(tx, block);
+  } catch (e) {
+    this.drop();
+    throw e;
+  }
+
+  yield this.commit();
+
+  return details;
+});
+
+/**
+ * Attempt to confirm a transaction.
+ * @private
+ * @param {TX} tx
+ * @returns {Promise}
+ */
+
+TXDB.prototype._confirm = co(function* confirm(tx, block) {
   var hash = tx.hash('hex');
   var height = block ? block.height : this.walletdb.height;
   var details = new Details(this, tx, height);
   var i, account, output, coin, input, prevout;
   var path, credit, credits;
 
+  assert(tx.height !== -1);
+
   if (!tx.isCoinbase()) {
     credits = yield this.getSpentCredits(tx);
 
@@ -1427,10 +1463,7 @@ TXDB.prototype.erase = co(function* erase(tx) {
       this.del(layout.H(account, tx.height, hash));
   }
 
-  if (yield this.removeTXRecord(tx)) {
-    if (tx.block)
-      yield this.removeBlockRecord(tx, tx.block);
-  }
+  yield this.removeTXRecord(tx);
 
   // Update the transaction counter
   // and commit new state due to
@@ -1601,6 +1634,8 @@ TXDB.prototype.disconnect = co(function* disconnect(tx, block) {
     this.saveCredit(credit, path);
   }
 
+  yield this.removeBlockRecord(tx, block.height);
+
   // We need to update the now-removed
   // block properties and reindex due
   // to the height change.
@@ -3168,10 +3203,16 @@ DetailsMember.prototype.toJSON = function toJSON(network) {
  * Helpers
  */
 
-function Orphan(tx, index) {
+function Orphan(tx, index, block) {
   this.tx = tx;
   this.hash = tx.hash('hex');
   this.index = index;
+  this.block = block || null;
+}
+
+function ResolvedOrphan(tx, block) {
+  this.tx = tx;
+  this.block = block || null;
 }
 
 function cmp(a, b) {
diff --git a/lib/wallet/wallet.js b/lib/wallet/wallet.js
index 8b64734b..270cdb41 100644
--- a/lib/wallet/wallet.js
+++ b/lib/wallet/wallet.js
@@ -1833,13 +1833,14 @@ Wallet.prototype.add = co(function* add(tx, block) {
 Wallet.prototype._add = co(function* add(tx, block) {
   var resolved = yield this.txdb.resolve(tx, block);
   var result = false;
-  var i;
+  var i, orphan;
 
   if (resolved.length === 0)
     return true;
 
   for (i = 0; i < resolved.length; i++) {
-    if (yield this._insert(resolved[i], block))
+    orphan = resolved[i];
+    if (yield this._insert(orphan.tx, orphan.block))
       result = true;
   }
 
@@ -1891,6 +1892,21 @@ Wallet.prototype.unconfirm = co(function* unconfirm(hash, block) {
   }
 });
 
+/**
+ * Confirm a wallet transcation.
+ * @param {Hash} hash
+ * @returns {Promise}
+ */
+
+Wallet.prototype.confirm = co(function* confirm(hash, block) {
+  var unlock = yield this.writeLock.lock();
+  try {
+    return yield this.txdb.confirm(hash, block);
+  } finally {
+    unlock();
+  }
+});
+
 /**
  * Remove a wallet transaction.
  * @param {Hash} hash
diff --git a/lib/wallet/walletdb.js b/lib/wallet/walletdb.js
index 8e5bd0c0..3f9f246d 100644
--- a/lib/wallet/walletdb.js
+++ b/lib/wallet/walletdb.js
@@ -26,6 +26,7 @@ var Bloom = require('../utils/bloom');
 var Logger = require('../node/logger');
 var TX = require('../primitives/tx');
 var TXDB = require('./txdb');
+var U32 = utils.U32;
 
 /*
  * Database Layout:
@@ -101,12 +102,15 @@ var layout = {
     return [key.readUInt32BE(1, true), key.toString('ascii', 5)];
   },
   R: new Buffer([0x52]),
-  b: function b(hash) {
-    var key = new Buffer(33);
+  b: function b(height) {
+    var key = new Buffer(5);
     key[0] = 0x62;
-    key.write(hash, 1, 'hex');
+    key.writeUInt32BE(height, 1, true);
     return key;
   },
+  bb: function bb(key) {
+    return key.readUInt32BE(1, true);
+  },
   e: function e(hash) {
     var key = new Buffer(33);
     key[0] = 0x65;
@@ -287,6 +291,21 @@ WalletDB.prototype.getDepth = co(function* getDepth() {
   return depth + 1;
 });
 
+/**
+ * Get current block height.
+ * @private
+ * @returns {Promise}
+ */
+
+WalletDB.prototype.getHeight = co(function* getHeight() {
+  var data = yield this.db.get(layout.R);
+
+  if (!data)
+    return -1;
+
+  return data.readUInt32LE(0, true);
+});
+
 /**
  * Start batch.
  * @private
@@ -538,14 +557,11 @@ WalletDB.prototype.save = function save(wallet) {
   var wid = wallet.wid;
   var id = wallet.id;
   var batch = this.batch(wallet);
-  var buf = new Buffer(4);
 
   this.widCache.set(id, wid);
 
   batch.put(layout.w(wid), wallet.toRaw());
-
-  buf.writeUInt32LE(wid, 0, true);
-  batch.put(layout.l(id), buf);
+  batch.put(layout.l(id), U32(wid));
 };
 
 /**
@@ -788,12 +804,9 @@ WalletDB.prototype.saveAccount = function saveAccount(account) {
   var index = account.accountIndex;
   var name = account.name;
   var batch = this.batch(wallet);
-  var buf = new Buffer(4);
-
-  buf.writeUInt32LE(index, 0, true);
 
   batch.put(layout.a(wid, index), account.toRaw());
-  batch.put(layout.i(wid, name), buf);
+  batch.put(layout.i(wid, name), U32(index));
 
   wallet.accountCache.set(index, account);
 };
@@ -1079,14 +1092,19 @@ WalletDB.prototype._rescan = co(function* rescan(chaindb, height) {
   var self = this;
   var hashes;
 
-  if (height == null)
-    height = this.height;
+  if (height == null) {
+    height = this.height - 36;
+    if (height < 0)
+      height = 0;
+  }
+
+  yield this.rollback(height);
 
   hashes = yield this.getHashes();
 
   this.logger.info('Scanning for %d addresses.', hashes.length);
 
-  yield chaindb.scan(height, hashes, function(block, txs) {
+  yield chaindb.scan(this.tip, hashes, function(block, txs) {
     return self._addBlock(block, txs);
   });
 });
@@ -1313,7 +1331,8 @@ WalletDB.prototype.writeGenesis = co(function* writeGenesis() {
  */
 
 WalletDB.prototype.getTip = co(function* getTip() {
-  var data = yield this.db.get(layout.R);
+  var height = yield this.getHeight();
+  var data = yield this.db.get(layout.b(height));
 
   if (!data)
     return;
@@ -1322,16 +1341,32 @@ WalletDB.prototype.getTip = co(function* getTip() {
 });
 
 /**
- * Write the best block hash.
+ * Write the tip immediately.
  * @param {Hash} hash
  * @param {Number} height
  * @returns {Promise}
  */
 
-WalletDB.prototype.setTip = co(function* setTip(hash, height) {
+WalletDB.prototype.setTip = function setTip(hash, height) {
   var block = new WalletBlock(hash, height);
+  return this.setBlock(block);
+};
 
-  yield this.db.put(layout.R, block.toTip());
+/**
+ * Write the connecting block immediately.
+ * @param {Hash} hash
+ * @param {Number} height
+ * @returns {Promise}
+ */
+
+WalletDB.prototype.setBlock = co(function* setBlock(block) {
+  var batch = this.db.batch();
+
+  batch.del(layout.b(block.height + 1));
+  batch.put(layout.b(block.height), block.toRaw());
+  batch.put(layout.R, U32(block.height));
+
+  yield batch.write();
 
   this.tip = block.hash;
   this.height = block.height;
@@ -1345,7 +1380,20 @@ WalletDB.prototype.setTip = co(function* setTip(hash, height) {
 
 WalletDB.prototype.writeBlock = function writeBlock(wallet, block) {
   var batch = this.batch(wallet);
-  batch.put(layout.b(block.hash), block.toRaw());
+  batch.put(layout.b(block.height), block.toRaw());
+  batch.put(layout.R, U32(block.height));
+};
+
+/**
+ * Connect a block.
+ * @param {WalletBlock} block
+ * @returns {Promise}
+ */
+
+WalletDB.prototype.unwriteBlock = function unwriteBlock(wallet, block) {
+  var batch = this.batch(wallet);
+  batch.del(layout.b(block.height));
+  batch.put(layout.R, U32(block.height - 1));
 };
 
 /**
@@ -1356,19 +1404,8 @@ WalletDB.prototype.writeBlock = function writeBlock(wallet, block) {
 
 WalletDB.prototype.writeTX = function writeTX(wallet, hash, wids) {
   var batch = this.batch(wallet);
-  this.addFilter(hash);
   batch.put(layout.e(hash), serializeWallets(wids));
-};
-
-/**
- * Connect a block.
- * @param {WalletBlock} block
- * @returns {Promise}
- */
-
-WalletDB.prototype.removeBlock = function removeBlock(wallet, block) {
-  var batch = this.batch(wallet);
-  batch.del(layout.b(block.hash));
+  this.addFilter(hash);
 };
 
 /**
@@ -1377,7 +1414,7 @@ WalletDB.prototype.removeBlock = function removeBlock(wallet, block) {
  * @returns {Promise}
  */
 
-WalletDB.prototype.removeTX = function removeTX(wallet, hash) {
+WalletDB.prototype.unwriteTX = function unwriteTX(wallet, hash) {
   var batch = this.batch(wallet);
   batch.del(layout.e(hash));
 };
@@ -1388,13 +1425,13 @@ WalletDB.prototype.removeTX = function removeTX(wallet, hash) {
  * @returns {Promise}
  */
 
-WalletDB.prototype.getBlock = co(function* getBlock(hash) {
-  var data = yield this.db.get(layout.b(hash));
+WalletDB.prototype.getBlock = co(function* getBlock(height) {
+  var data = yield this.db.get(layout.b(height));
 
   if (!data)
     return;
 
-  return WalletBlock.fromRaw(hash, data);
+  return WalletBlock.fromRaw(data);
 });
 
 /**
@@ -1412,6 +1449,28 @@ WalletDB.prototype.getWalletsByTX = co(function* getWalletsByTX(hash) {
   return parseWallets(data);
 });
 
+/**
+ * Sync with chain height.
+ * @param {Number} height
+ * @returns {Promise}
+ */
+
+WalletDB.prototype.rollback = co(function* rollback(height) {
+  var block;
+
+  if (this.height > height) {
+    this.logger.info(
+      'Rolling back %d blocks to height %d.',
+      this.height - height, height);
+  }
+
+  while (this.height > height) {
+    block = yield this.getBlock(this.height);
+    assert(block);
+    yield this._removeBlock(block);
+  }
+});
+
 /**
  * Add a block's transactions and write the new best hash.
  * @param {ChainEntry} entry
@@ -1421,6 +1480,7 @@ WalletDB.prototype.getWalletsByTX = co(function* getWalletsByTX(hash) {
 WalletDB.prototype.addBlock = co(function* addBlock(entry, txs) {
   var unlock = yield this.txLock.lock();
   try {
+    yield this.rollback(entry.height - 1);
     return yield this._addBlock(entry, txs);
   } finally {
     unlock();
@@ -1440,7 +1500,8 @@ WalletDB.prototype._addBlock = co(function* addBlock(entry, txs) {
 
   if (this.options.useCheckpoints) {
     if (entry.height <= this.network.checkpoints.lastHeight) {
-      yield this.setTip(entry.hash, entry.height);
+      block = WalletBlock.fromEntry(entry);
+      yield this.setBlock(block);
       return;
     }
   }
@@ -1456,12 +1517,18 @@ WalletDB.prototype._addBlock = co(function* addBlock(entry, txs) {
       total++;
   }
 
-  if (total > 0) {
-    this.logger.info('Connecting block %s (%d txs).',
-      utils.revHex(block.hash), total);
+  if (total === 0) {
+    yield this.setBlock(block);
+    return total;
   }
 
-  yield this.setTip(entry.hash, entry.height);
+  this.height = block.height;
+  this.tip = block.hash;
+
+  this.logger.info('Connected block %s (tx=%d).',
+    utils.revHex(block.hash), total);
+
+  return total;
 });
 
 /**
@@ -1474,6 +1541,7 @@ WalletDB.prototype._addBlock = co(function* addBlock(entry, txs) {
 WalletDB.prototype.removeBlock = co(function* removeBlock(entry) {
   var unlock = yield this.txLock.lock();
   try {
+    yield this.rollback(entry.height);
     return yield this._removeBlock(entry);
   } finally {
     unlock();
@@ -1488,24 +1556,34 @@ WalletDB.prototype.removeBlock = co(function* removeBlock(entry) {
  */
 
 WalletDB.prototype._removeBlock = co(function* removeBlock(entry) {
-  var block = WalletBlock.fromEntry(entry);
-  var data = yield this.getBlock(block.hash);
-  var i, hash;
+  var block = yield this.getBlock(entry.height);
+  var i, tx, prev;
 
-  if (data)
-    block.hashes = data.hashes;
+  if (!block)
+    return;
 
-  if (block.hashes.length > 0) {
-    this.logger.warning('Disconnecting block %s (%d txs).',
-      utils.revHex(block.hash), block.hashes.length);
+  assert(block.height > 0);
+
+  prev = yield this.getBlock(entry.height - 1);
+  assert(prev);
+
+  if (block.txs.length === 0) {
+    yield this.setBlock(prev);
+    return block.txs.length;
   }
 
-  for (i = block.hashes.length - 1; i >= 0; i--) {
-    hash = block.hashes[i];
-    yield this._unconfirmTX(hash, block);
+  for (i = block.txs.length - 1; i >= 0; i--) {
+    tx = block.txs[i];
+    yield this._unconfirmTX(tx, block);
   }
 
-  yield this.setTip(block.prevBlock, block.height - 1);
+  this.height = prev.height;
+  this.tip = prev.hash;
+
+  this.logger.warning('Disconnected block %s (tx=%d).',
+    utils.revHex(block.hash), block.txs.length);
+
+  return block.txs.length;
 });
 
 /**
@@ -1568,17 +1646,21 @@ WalletDB.prototype._insertTX = co(function* insertTX(tx, block) {
 });
 
 /**
- * Unconfirm a transaction from all relevant wallets.
- * @param {Hash} hash
+ * Confirm a transaction from all
+ * relevant wallets without a lock.
+ * @private
+ * @param {TXHash} hash
  * @returns {Promise}
  */
 
-WalletDB.prototype.unconfirmTX = co(function* unconfirmTX(hash, block) {
-  var unlock = yield this.txLock.lock();
-  try {
-    return yield this._unconfirmTX(hash, block);
-  } finally {
-    unlock();
+WalletDB.prototype._confirmTX = co(function* confirmTX(tx, block) {
+  var i, wid, wallet;
+
+  for (i = 0; i < tx.wids.length; i++) {
+    wid = tx.wids[i];
+    wallet = yield this.get(wid);
+    assert(wallet);
+    yield wallet.confirm(tx.hash, block);
   }
 });
 
@@ -1586,22 +1668,18 @@ WalletDB.prototype.unconfirmTX = co(function* unconfirmTX(hash, block) {
  * Unconfirm a transaction from all
  * relevant wallets without a lock.
  * @private
- * @param {Hash} hash
+ * @param {TXHash} hash
  * @returns {Promise}
  */
 
-WalletDB.prototype._unconfirmTX = co(function* unconfirmTX(hash, block) {
-  var wids = yield this.getWalletsByTX(hash);
+WalletDB.prototype._unconfirmTX = co(function* unconfirmTX(tx, block) {
   var i, wid, wallet;
 
-  if (!wids)
-    return;
-
-  for (i = 0; i < wids.length; i++) {
-    wid = wids[i];
+  for (i = 0; i < tx.wids.length; i++) {
+    wid = tx.wids[i];
     wallet = yield this.get(wid);
     assert(wallet);
-    yield wallet.unconfirm(hash, block);
+    yield wallet.unconfirm(tx.hash, block);
   }
 });
 
@@ -1652,8 +1730,8 @@ function WalletBlock(hash, height) {
 
   this.hash = hash || constants.NULL_HASH;
   this.height = height != null ? height : -1;
-  this.prevBlock = constants.NULL_HASH;
-  this.hashes = [];
+  this.txs = [];
+  this.index = {};
 }
 
 /**
@@ -1662,10 +1740,7 @@ function WalletBlock(hash, height) {
  */
 
 WalletBlock.prototype.clone = function clone() {
-  var block = new WalletBlock(this.hash, this.height);
-  block.prevBlock = this.prevBlock;
-  block.hashes = this.hashes.slice();
-  return block;
+  return new WalletBlock(this.hash, this.height);
 };
 
 /**
@@ -1677,7 +1752,6 @@ WalletBlock.prototype.clone = function clone() {
 WalletBlock.prototype.fromEntry = function fromEntry(entry) {
   this.hash = entry.hash;
   this.height = entry.height;
-  this.prevBlock = entry.prevBlock;
   return this;
 };
 
@@ -1690,8 +1764,6 @@ WalletBlock.prototype.fromEntry = function fromEntry(entry) {
 WalletBlock.prototype.fromJSON = function fromJSON(json) {
   this.hash = utils.revHex(json.hash);
   this.height = json.height;
-  if (json.prevBlock)
-    this.prevBlock = utils.revHex(json.prevBlock);
   return this;
 };
 
@@ -1702,12 +1774,23 @@ WalletBlock.prototype.fromJSON = function fromJSON(json) {
  * @param {Buffer} data
  */
 
-WalletBlock.prototype.fromRaw = function fromRaw(hash, data) {
+WalletBlock.prototype.fromRaw = function fromRaw(data) {
   var p = new BufferReader(data);
-  this.hash = hash;
+  var i, hash, tx, count;
+
+  this.hash = p.readHash('hex');
   this.height = p.readU32();
-  while (p.left())
-    this.hashes.push(p.readHash('hex'));
+
+  while (p.left()) {
+    hash = p.readHash('hex');
+    tx = new TXHash(hash);
+    count = p.readVarint();
+    for (i = 0; i < count; i++)
+      tx.wids.push(p.readU32());
+    this.txs.push(tx);
+    this.index[tx.hash] = tx;
+  }
+
   return this;
 };
 
@@ -1751,8 +1834,8 @@ WalletBlock.fromJSON = function fromJSON(json) {
  * @returns {WalletBlock}
  */
 
-WalletBlock.fromRaw = function fromRaw(hash, data) {
-  return new WalletBlock().fromRaw(hash, data);
+WalletBlock.fromRaw = function fromRaw(data) {
+  return new WalletBlock().fromRaw(data);
 };
 
 /**
@@ -1790,12 +1873,18 @@ WalletBlock.prototype.toTip = function toTip(writer) {
 
 WalletBlock.prototype.toRaw = function toRaw(writer) {
   var p = new BufferWriter(writer);
-  var i;
+  var i, j, tx;
 
+  p.writeHash(this.hash);
   p.writeU32(this.height);
 
-  for (i = 0; i < this.hashes.length; i++)
-    p.writeHash(this.hashes[i]);
+  for (i = 0; i < this.txs.length; i++) {
+    tx = this.txs[i];
+    p.writeHash(tx.hash);
+    p.writeVarint(tx.wids.length);
+    for (j = 0; j < tx.wids.length; j++)
+      p.writeU32(tx.wids[j]);
+  }
 
   if (!writer)
     p = p.render();
@@ -1803,6 +1892,61 @@ WalletBlock.prototype.toRaw = function toRaw(writer) {
   return p;
 };
 
+/**
+ * Add a hash and wid pair to the block.
+ * @param {Hash} hash
+ * @param {WalletID} wid
+ * @returns {Boolean}
+ */
+
+WalletBlock.prototype.add = function add(hash, wid) {
+  var tx = this.index[hash];
+  var index;
+
+  if (!tx) {
+    tx = new TXHash(hash);
+    tx.wids.push(wid);
+    this.txs.push(tx);
+    this.index[tx.hash] = tx;
+    return true;
+  }
+
+  index = utils.binaryInsert(tx.wids, wid, cmp, true);
+
+  if (index === -1)
+    return false;
+
+  return true;
+};
+
+/**
+ * Remove a hash and wid pair from the block.
+ * @param {Hash} hash
+ * @param {WalletID} wid
+ * @returns {Boolean}
+ */
+
+WalletBlock.prototype.remove = function remove(hash, wid) {
+  var tx = this.index[hash];
+  var result;
+
+  if (!tx)
+    return false;
+
+  result = utils.binaryRemove(tx.wids, wid, cmp);
+
+  if (!result)
+    return false;
+
+  if (tx.wids.length === 0) {
+    result = utils.binaryRemove(this.txs, tx, cmpid);
+    assert(result);
+    delete this.index[tx.hash];
+  }
+
+  return true;
+};
+
 /**
  * Convert the block to a more json-friendly object.
  * @returns {Object}
@@ -1819,6 +1963,14 @@ WalletBlock.prototype.toJSON = function toJSON() {
  * Helpers
  */
 
+function TXHash(hash, wids) {
+  this.hash = hash || constants.NULL_HASH;
+  this.wids = wids || [];
+  this.id = TXHash.id++;
+}
+
+TXHash.id = 0;
+
 function parseWallets(data) {
   var p = new BufferReader(data);
   var wids = [];
@@ -1845,6 +1997,10 @@ function cmp(a, b) {
   return a - b;
 }
 
+function cmpid(a, b) {
+  return a.id - b.id;
+}
+
 /*
  * Expose
  */