diff --git a/src/db/db/dbHierNetworkProcessor.cc b/src/db/db/dbHierNetworkProcessor.cc
index 82c1a89d7..6bad4c7fb 100644
--- a/src/db/db/dbHierNetworkProcessor.cc
+++ b/src/db/db/dbHierNetworkProcessor.cc
@@ -1241,7 +1241,148 @@ hier_clusters<T>::clusters_per_cell (db::cell_index_type cell_index)
   return c->second;
 }
 
+template <class T>
+static
+void put_or_propagate (const hier_clusters<T> &hc, incoming_cluster_connections<T> &inc, size_t cluster_id, const local_cluster<T> &cluster, db::Layout &layout, db::cell_index_type ci, const std::map<unsigned int, unsigned int> &lm, const db::ICplxTrans &trans)
+{
+  db::Cell &target_cell = layout.cell (ci);
+
+  if (cluster_id > 0 && inc.has_incoming (ci, cluster_id)) {
+
+    typedef std::pair<db::cell_index_type, db::InstElement> reference_type;
+    std::map<reference_type, bool> references;
+
+    for (db::Cell::parent_inst_iterator pi = target_cell.begin_parent_insts (); ! pi.at_end (); ++pi) {
+      db::Instance i = pi->child_inst ();
+      for (db::CellInstArray::iterator ii = i.cell_inst ().begin (); ! ii.at_end (); ++ii) {
+        references.insert (std::make_pair (reference_type ((*pi).parent_cell_index (), db::InstElement (i, ii)), false));
+      }
+    }
+
+    const typename incoming_cluster_connections<T>::incoming_connections &connections = inc.incoming (ci, cluster_id);
+    for (typename incoming_cluster_connections<T>::incoming_connections::const_iterator x = connections.begin (); x != connections.end (); ++x) {
+      typename std::map<reference_type, bool>::iterator r = references.find (reference_type (x->parent_cell (), x->inst ()));
+      if (r != references.end () && ! r->second) {
+        put_or_propagate (hc, inc, x->parent_cluster_id (), cluster, layout, r->first.first, lm, r->first.second.complex_trans () * trans);
+        r->second = true;
+      }
+    }
+
+    for (typename std::map<reference_type, bool>::const_iterator r = references.begin (); r != references.end (); ++r) {
+      if (! r->second) {
+        put_or_propagate (hc, inc, 0, cluster, layout, r->first.first, lm, r->first.second.complex_trans () * trans);
+      }
+    }
+
+  } else {
+
+    for (typename std::map<unsigned int, unsigned int>::const_iterator m = lm.begin (); m != lm.end (); ++m) {
+      db::Shapes shapes;
+      for (typename local_cluster<T>::shape_iterator s = cluster.begin (m->first); ! s.at_end (); ++s) {
+        shapes.insert (*s);
+      }
+      tl::ident_map<db::properties_id_type> pm;
+      target_cell.shapes (m->second).insert_transformed (shapes, trans, pm);
+    }
+
+  }
+}
+
+template <class T>
+void
+hier_clusters<T>::return_to_hierarchy (db::Layout &layout, db::Cell &cell, const std::map<unsigned int, unsigned int> &lm) const
+{
+  incoming_cluster_connections<T> inc (layout, cell, *this);
+
+  for (db::Layout::bottom_up_iterator c = layout.begin_bottom_up (); c != layout.end_bottom_up (); ++c) {
+    const db::connected_clusters<T> &cc = clusters_per_cell (*c);
+    for (typename db::connected_clusters<T>::const_iterator lc = cc.begin (); lc != cc.end (); ++lc) {
+      put_or_propagate (*this, inc, lc->id (), *lc, layout, *c, lm, db::ICplxTrans ());
+    }
+  }
+}
+
 //  explicit instantiations
 template class DB_PUBLIC hier_clusters<db::PolygonRef>;
 
+// ------------------------------------------------------------------------------
+//  incoming_cluster_connections implementation
+
+template <class T>
+incoming_cluster_connections<T>::incoming_cluster_connections (const db::Layout &layout, const db::Cell &cell, const hier_clusters<T> &hc)
+  : mp_layout (const_cast<db::Layout *> (&layout)), mp_hc (const_cast<hier_clusters<T> *> (&hc))
+{
+  cell.collect_called_cells (m_called_cells);
+  m_called_cells.insert (cell.cell_index ());
+}
+
+template <class T>
+bool
+incoming_cluster_connections<T>::has_incoming (db::cell_index_type ci, size_t cluster_id) const
+{
+  std::map<db::cell_index_type, std::map<size_t, incoming_connections> >::const_iterator i = m_incoming.find (ci);
+  if (i == m_incoming.end ()) {
+    ensure_computed (ci);
+    i = m_incoming.find (ci);
+    tl_assert (i != m_incoming.end ());
+  }
+
+  tl_assert (i != m_incoming.end ());
+  return (i->second.find (cluster_id) != i->second.end ());
+}
+
+template <class T>
+const typename incoming_cluster_connections<T>::incoming_connections &
+incoming_cluster_connections<T>::incoming (db::cell_index_type ci, size_t cluster_id) const
+{
+  std::map<db::cell_index_type, std::map<size_t, incoming_connections> >::const_iterator i = m_incoming.find (ci);
+  if (i == m_incoming.end ()) {
+    ensure_computed (ci);
+    i = m_incoming.find (ci);
+    tl_assert (i != m_incoming.end ());
+  }
+
+  std::map<size_t, incoming_connections>::const_iterator ii = i->second.find (cluster_id);
+  if (ii != i->second.end ()) {
+    return ii->second;
+  } else {
+    static incoming_connections empty;
+    return empty;
+  }
+}
+
+template <class T>
+void
+incoming_cluster_connections<T>::ensure_computed (db::cell_index_type ci) const
+{
+  tl_assert (mp_layout.get () != 0);
+  m_incoming.insert (std::make_pair (ci, std::map<size_t, incoming_connections> ()));
+
+  const db::Cell &cell = mp_layout->cell (ci);
+  for (db::Cell::parent_cell_iterator pc = cell.begin_parent_cells (); pc != cell.end_parent_cells (); ++pc) {
+    if (m_called_cells.find (*pc) != m_called_cells.end ()) {
+      ensure_computed_parent (*pc);
+    }
+  }
+
+  m_called_cells.erase (ci);
+}
+
+template <class T>
+void
+incoming_cluster_connections<T>::ensure_computed_parent (db::cell_index_type ci) const
+{
+  ensure_computed (ci);
+
+  const connected_clusters<T> &cc = ((const hier_clusters<T> *) mp_hc.get ())->clusters_per_cell (ci);
+  for (typename connected_clusters<T>::connections_iterator x = cc.begin_connections (); x != cc.end_connections (); ++x) {
+    for (typename connected_clusters<T>::connections_type::const_iterator xx = x->second.begin (); xx != x->second.end (); ++xx) {
+      m_incoming [xx->inst ().inst_ptr.cell_index ()][xx->id ()].push_back (IncomingClusterInstance (ci, x->first, xx->inst ()));
+    }
+  }
+}
+
+//  explicit instantiations
+template class DB_PUBLIC incoming_cluster_connections<db::PolygonRef>;
+
 }
diff --git a/src/db/db/dbHierNetworkProcessor.h b/src/db/db/dbHierNetworkProcessor.h
index 108b185e1..e102a5d26 100644
--- a/src/db/db/dbHierNetworkProcessor.h
+++ b/src/db/db/dbHierNetworkProcessor.h
@@ -443,6 +443,7 @@ public:
   typedef std::list<ClusterInstance> connections_type;
   typedef typename local_clusters<T>::box_type box_type;
   typedef connected_clusters_iterator<T> all_iterator;
+  typedef typename std::map<typename local_cluster<T>::id_type, connections_type>::const_iterator connections_iterator;
 
   /**
    *  @brief Constructor
@@ -488,6 +489,24 @@ public:
     return connected_clusters_iterator<T> (*this);
   }
 
+  /**
+   *  @brief Begin iterator for the connections
+   *
+   *  The iterated object is a pair or (cluster id, connections_type).
+   */
+  connections_iterator begin_connections () const
+  {
+    return m_connections.begin ();
+  }
+
+  /**
+   *  @brief Begin iterator for the connections
+   */
+  connections_iterator end_connections () const
+  {
+    return m_connections.end ();
+  }
+
 private:
   template<typename> friend class connected_clusters_iterator;
 
@@ -519,6 +538,7 @@ template <typename> class cell_clusters_box_converter;
  */
 template <class T>
 class DB_PUBLIC hier_clusters
+  : public tl::Object
 {
 public:
   typedef typename local_cluster<T>::box_type box_type;
@@ -543,6 +563,18 @@ public:
    */
   connected_clusters<T> &clusters_per_cell (db::cell_index_type cell_index);
 
+  /**
+   *  @brief Writes the net shapes back to the original hierarchy
+   *
+   *  The layout object is supposed to be the original layout or one with identical cell indexes.
+   *  "lm" is a layer mapping table from the connection layer indexes to the target layer
+   *  indexes.
+   *
+   *  The backannotation process usually involves propagation of shapes up in the hierarchy
+   *  to resolve variants.
+   */
+  void return_to_hierarchy (db::Layout &layout, db::Cell &cell, const std::map<unsigned int, unsigned int> &lm) const;
+
   /**
    *  @brief Clears this collection
    */
@@ -557,6 +589,103 @@ private:
   std::map<db::cell_index_type, connected_clusters<T> > m_per_cell_clusters;
 };
 
+/**
+ *  @brief A connection to a cluster from a parent cluster
+ */
+class DB_PUBLIC IncomingClusterInstance
+{
+public:
+  IncomingClusterInstance (db::cell_index_type pc, size_t parent_cluster_id, const db::InstElement &inst)
+    : m_parent_cell (pc), m_parent_cluster_id (parent_cluster_id), m_inst (inst)
+  {
+    //  .. nothing yet ..
+  }
+
+  IncomingClusterInstance ()
+    : m_parent_cell (0), m_parent_cluster_id (0), m_inst ()
+  {
+    //  .. nothing yet ..
+  }
+
+  /**
+   *  @brief Gets the cell index of the parent cell
+   */
+  size_t parent_cell () const
+  {
+    return m_parent_cell;
+  }
+
+  /**
+   *  @brief Gets the cluster ID from which the cluster is connected to
+   *  The parent cluster lives in the parent cell
+   */
+  size_t parent_cluster_id () const
+  {
+    return m_parent_cluster_id;
+  }
+
+  /**
+   *  @brief Gets the instance path
+   */
+  const db::InstElement &inst () const
+  {
+    return m_inst;
+  }
+
+  /**
+   *  @brief Equality
+   */
+  bool operator== (const IncomingClusterInstance &other) const
+  {
+    return m_parent_cluster_id == other.m_parent_cluster_id && m_parent_cell == other.m_parent_cell && m_inst == other.m_inst;
+  }
+
+  /**
+   *  @brief Less operator
+   */
+  bool operator< (const IncomingClusterInstance &other) const
+  {
+    if (m_parent_cluster_id != other.m_parent_cluster_id) {
+      return m_parent_cluster_id < other.m_parent_cluster_id;
+    }
+    if (m_parent_cell != other.m_parent_cell) {
+      return m_parent_cell < other.m_parent_cell;
+    }
+    return m_inst < other.m_inst;
+  }
+
+private:
+  db::cell_index_type m_parent_cell;
+  size_t m_parent_cluster_id;
+  db::InstElement m_inst;
+};
+
+/**
+ *  @brief A class holding the parent relationships for clusters of cells
+ *
+ *  This class can be used to quickly identify the connections made to a specific cluster from a parent cluster.
+ */
+template <class T>
+class incoming_cluster_connections
+{
+public:
+  typedef std::list<IncomingClusterInstance> incoming_connections;
+
+  incoming_cluster_connections (const db::Layout &layout, const db::Cell &cell, const hier_clusters<T> &hc);
+
+  bool has_incoming (db::cell_index_type ci, size_t cluster_id) const;
+  const incoming_connections &incoming (db::cell_index_type ci, size_t cluster_id) const;
+
+private:
+  mutable std::set<db::cell_index_type> m_called_cells;
+  mutable std::map<db::cell_index_type, std::map<size_t, incoming_connections> > m_incoming;
+  tl::weak_ptr<db::Layout> mp_layout;
+  tl::weak_ptr<hier_clusters<T> > mp_hc;
+
+  void ensure_computed (db::cell_index_type ci) const;
+  void ensure_computed_parent (db::cell_index_type ci) const;
+};
+
 }
 
 #endif
diff --git a/src/db/unit_tests/dbHierNetworkProcessorTests.cc b/src/db/unit_tests/dbHierNetworkProcessorTests.cc
index fab9c5d49..d527e4b7d 100644
--- a/src/db/unit_tests/dbHierNetworkProcessorTests.cc
+++ b/src/db/unit_tests/dbHierNetworkProcessorTests.cc
@@ -546,57 +546,129 @@ static void run_hc_test (tl::TestBase *_this, const std::string &file, const std
   db::compare_layouts (_this, ly, tl::testsrc () + "/testdata/algo/" + au_file);
 }
 
+static void run_hc_test_with_backannotation (tl::TestBase *_this, const std::string &file, const std::string &au_file)
+{
+  db::Layout ly;
+  unsigned int l1 = 0, l2 = 0, l3 = 0;
+
+  {
+    db::LayerProperties p;
+    db::LayerMap lmap;
+
+    p.layer = 1;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l1 = ly.insert_layer ());
+    ly.set_properties (l1, p);
+
+    p.layer = 2;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l2 = ly.insert_layer ());
+    ly.set_properties (l2, p);
+
+    p.layer = 3;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l3 = ly.insert_layer ());
+    ly.set_properties (l3, p);
+
+    db::LoadLayoutOptions options;
+    options.get_options<db::CommonReaderOptions> ().layer_map = lmap;
+    options.get_options<db::CommonReaderOptions> ().create_other_layers = false;
+
+    std::string fn (tl::testsrc ());
+    fn += "/testdata/algo/";
+    fn += file;
+    tl::InputStream stream (fn);
+    db::Reader reader (stream);
+    reader.read (ly, options);
+  }
+
+  normalize_layer (ly, l1);
+  normalize_layer (ly, l2);
+  normalize_layer (ly, l3);
+
+  //  connect 1 to 1, 1 to 2 and 1 to 3, but *not* 2 to 3
+  db::Connectivity conn;
+  conn.connect (l1, l1);
+  conn.connect (l2, l2);
+  conn.connect (l3, l3);
+  conn.connect (l1, l2);
+  conn.connect (l1, l3);
+
+  db::hier_clusters<db::PolygonRef> hc;
+  hc.build (ly, ly.cell (*ly.begin_top_down ()), db::ShapeIterator::Polygons, conn);
+
+  std::map<unsigned int, unsigned int> lm;
+  lm[l1] = ly.insert_layer (db::LayerProperties (101, 0));
+  lm[l2] = ly.insert_layer (db::LayerProperties (102, 0));
+  lm[l3] = ly.insert_layer (db::LayerProperties (103, 0));
+  hc.return_to_hierarchy (ly, ly.cell (*ly.begin_top_down ()), lm);
+
+  CHECKPOINT();
+  db::compare_layouts (_this, ly, tl::testsrc () + "/testdata/algo/" + au_file);
+}
+
 TEST(41_HierClusters)
 {
   run_hc_test (_this, "hc_test_l1.gds", "hc_test_au1.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l1.gds", "hc_test_au1b.gds");
 }
 
 TEST(42_HierClusters)
 {
   run_hc_test (_this, "hc_test_l2.gds", "hc_test_au2.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l2.gds", "hc_test_au2b.gds");
 }
 
 TEST(43_HierClusters)
 {
   run_hc_test (_this, "hc_test_l3.gds", "hc_test_au3.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l3.gds", "hc_test_au3b.gds");
 }
 
 TEST(44_HierClusters)
 {
   run_hc_test (_this, "hc_test_l4.gds", "hc_test_au4.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l4.gds", "hc_test_au4b.gds");
 }
 
 TEST(45_HierClusters)
 {
   run_hc_test (_this, "hc_test_l5.gds", "hc_test_au5.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l5.gds", "hc_test_au5b.gds");
 }
 
 TEST(46_HierClusters)
 {
   run_hc_test (_this, "hc_test_l6.gds", "hc_test_au6.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l6.gds", "hc_test_au6b.gds");
 }
 
 TEST(47_HierClusters)
 {
   run_hc_test (_this, "hc_test_l7.gds", "hc_test_au7.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l7.gds", "hc_test_au7b.gds");
 }
 
 TEST(48_HierClusters)
 {
   run_hc_test (_this, "hc_test_l8.gds", "hc_test_au8.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l8.gds", "hc_test_au8b.gds");
 }
 
 TEST(49_HierClusters)
 {
   run_hc_test (_this, "hc_test_l9.gds", "hc_test_au9.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l9.gds", "hc_test_au9b.gds");
 }
 
 TEST(50_HierClusters)
 {
   run_hc_test (_this, "hc_test_l10.gds", "hc_test_au10.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l10.gds", "hc_test_au10b.gds");
 }
 
 TEST(51_HierClusters)
 {
   run_hc_test (_this, "hc_test_l11.gds", "hc_test_au11.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l4.gds", "hc_test_au4b.gds");
 }
diff --git a/testdata/algo/hc_test_au10b.gds b/testdata/algo/hc_test_au10b.gds
new file mode 100644
index 000000000..56a41f98c
Binary files /dev/null and b/testdata/algo/hc_test_au10b.gds differ
diff --git a/testdata/algo/hc_test_au1b.gds b/testdata/algo/hc_test_au1b.gds
new file mode 100644
index 000000000..e1f2615cf
Binary files /dev/null and b/testdata/algo/hc_test_au1b.gds differ
diff --git a/testdata/algo/hc_test_au2b.gds b/testdata/algo/hc_test_au2b.gds
new file mode 100644
index 000000000..cd520f4de
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diff --git a/testdata/algo/hc_test_au3b.gds b/testdata/algo/hc_test_au3b.gds
new file mode 100644
index 000000000..9767fc7a0
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diff --git a/testdata/algo/hc_test_au4b.gds b/testdata/algo/hc_test_au4b.gds
new file mode 100644
index 000000000..1855f963d
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diff --git a/testdata/algo/hc_test_au5b.gds b/testdata/algo/hc_test_au5b.gds
new file mode 100644
index 000000000..b33c783ae
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diff --git a/testdata/algo/hc_test_au6b.gds b/testdata/algo/hc_test_au6b.gds
new file mode 100644
index 000000000..903d59d5f
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diff --git a/testdata/algo/hc_test_au7b.gds b/testdata/algo/hc_test_au7b.gds
new file mode 100644
index 000000000..457f97e87
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diff --git a/testdata/algo/hc_test_au8b.gds b/testdata/algo/hc_test_au8b.gds
new file mode 100644
index 000000000..816bb74d3
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diff --git a/testdata/algo/hc_test_au9b.gds b/testdata/algo/hc_test_au9b.gds
new file mode 100644
index 000000000..3e89d8674
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