diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 36682775..19c29c7c 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -345,6 +345,17 @@ Chain.prototype.add = function add(block) {
     this.orphan.count--;
   } while (true);
 
+  // Failsafe for large orphan chains
+  if (this.orphan.count > 10000) {
+    this.orphan.map = {};
+    this.orphan.bmap = {};
+    this.orphan.count = 0;
+  }
+
+  // No need to have a huge chain
+  // if (this.size() > 100000)
+  //   this.compact();
+
   // Compress old blocks
   this._compress();
 
@@ -652,36 +663,19 @@ Chain.prototype.retarget = function retarget(last, firstTs) {
   assert(false);
 };
 
-Chain.prototype.compact = function compact() {
-  assert(false);
+Chain.prototype.compact = function compact(keep) {
+  var index = this._compact(keep);
+  this.index.hashes = index.hashes;
+  this.index.ts = index.ts;
+  this.index.heights = index.heights;
+  this.index.bloom.reset();
+  this.index.hashes.forEach(function(hash) {
+    this.index.bloom.add(hash, 'hex');
+  }, this);
 };
 
-Chain.prototype._save = function(hash, obj) {
-  var self = this;
-
-  if (!this.storage)
-    return;
-
-  this.storage.put(this.prefix + hash, obj, function(err) {
-    if (err)
-      self.emit('error', err);
-  });
-};
-
-Chain.prototype._delete = function(hash) {
-  var self = this;
-
-  if (!this.storage)
-    return;
-
-  this.storage.del(this.prefix + hash, function(err) {
-    if (err)
-      self.emit('error', err);
-  });
-};
-
-Chain.prototype.toJSON = function toJSON() {
-  var keep = 1000;
+Chain.prototype._compact = function _compact(keep) {
+  keep = keep || 1000;
 
   // Keep only last 1000 consequent blocks, dilate others at:
   // 7 day range for blocks before 2013
@@ -728,15 +722,48 @@ Chain.prototype.toJSON = function toJSON() {
   }
 
   return {
-    v: 1,
-    type: 'chain',
-    network: network.type,
     hashes: first.hashes.concat(last.hashes),
     ts: first.ts.concat(last.ts),
     heights: first.heights.concat(last.heights)
   };
 };
 
+Chain.prototype._save = function(hash, obj) {
+  var self = this;
+
+  if (!this.storage)
+    return;
+
+  this.storage.put(this.prefix + hash, obj, function(err) {
+    if (err)
+      self.emit('error', err);
+  });
+};
+
+Chain.prototype._delete = function(hash) {
+  var self = this;
+
+  if (!this.storage)
+    return;
+
+  this.storage.del(this.prefix + hash, function(err) {
+    if (err)
+      self.emit('error', err);
+  });
+};
+
+Chain.prototype.toJSON = function toJSON() {
+  var index = this._compact();
+  return {
+    v: 1,
+    type: 'chain',
+    network: network.type,
+    hashes: index.hashes,
+    ts: index.ts,
+    heights: index.heights
+  };
+};
+
 Chain.prototype.fromJSON = function fromJSON(json) {
   var i;
 
diff --git a/lib/bcoin/fullchain.js b/lib/bcoin/fullchain.js
index 8554abed..7d66bf1e 100644
--- a/lib/bcoin/fullchain.js
+++ b/lib/bcoin/fullchain.js
@@ -260,6 +260,13 @@ Chain.prototype.add = function add(block) {
     this.orphan.count--;
   }
 
+  // Failsafe for large orphan chains
+  if (this.orphan.count > 10000) {
+    this.orphan.map = {};
+    this.orphan.bmap = {};
+    this.orphan.count = 0;
+  }
+
   return err;
 };
 
@@ -537,7 +544,6 @@ Chain.prototype._delete = function(hash) {
 
 Chain.prototype.toJSON = function toJSON() {
   var entries = this.index.entries;
-
   return {
     v: 1,
     type: 'chain',