diff --git a/src/main/java/com/metaweb/gridworks/model/Cell.java b/src/main/java/com/metaweb/gridworks/model/Cell.java
index 982bf473c..3d27d4d43 100644
--- a/src/main/java/com/metaweb/gridworks/model/Cell.java
+++ b/src/main/java/com/metaweb/gridworks/model/Cell.java
@@ -4,6 +4,7 @@ import java.io.Serializable;
 import java.io.Writer;
 import java.util.Calendar;
 import java.util.Date;
+import java.util.Map;
 import java.util.Properties;
 
 import org.json.JSONException;
@@ -76,11 +77,11 @@ public class Cell implements HasFields, Jsonizable {
         }
     }
     
-    static public Cell load(String s) throws Exception {
-        return s.length() == 0 ? null : load(ParsingUtilities.evaluateJsonStringToObject(s));
+    static public Cell load(String s, Map<Long, Recon> reconCache) throws Exception {
+        return s.length() == 0 ? null : load(ParsingUtilities.evaluateJsonStringToObject(s), reconCache);
     }
     
-    static public Cell load(JSONObject obj) throws Exception {
+    static public Cell load(JSONObject obj, Map<Long, Recon> reconCache) throws Exception {
         Serializable value = null;
         Recon recon = null;
         
@@ -97,7 +98,7 @@ public class Cell implements HasFields, Jsonizable {
         }
         
         if (obj.has("r") && !obj.isNull("r")) {
-            recon = Recon.load(obj.getJSONObject("r"));
+            recon = Recon.load(obj.getJSONObject("r"), reconCache);
         }
         
         return new Cell(value, recon);
diff --git a/src/main/java/com/metaweb/gridworks/model/Project.java b/src/main/java/com/metaweb/gridworks/model/Project.java
index adefcf401..24ad7facd 100644
--- a/src/main/java/com/metaweb/gridworks/model/Project.java
+++ b/src/main/java/com/metaweb/gridworks/model/Project.java
@@ -12,7 +12,9 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
@@ -195,10 +197,11 @@ public class Project {
             } else if ("rowCount".equals(field)) {
                 int count = Integer.parseInt(value);
                 
+                Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
                 for (int i = 0; i < count; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                    	Row row = Row.load(line);
+                    	Row row = Row.load(line, reconCache);
                         project.rows.add(row);
                         maxCellCount = Math.max(maxCellCount, row.cells.size());
                     }
diff --git a/src/main/java/com/metaweb/gridworks/model/Recon.java b/src/main/java/com/metaweb/gridworks/model/Recon.java
index b0ea56ecb..bd8007ecb 100644
--- a/src/main/java/com/metaweb/gridworks/model/Recon.java
+++ b/src/main/java/com/metaweb/gridworks/model/Recon.java
@@ -193,12 +193,17 @@ public class Recon implements HasFields, Jsonizable {
         writer.endObject();
     }
     
-    static public Recon load(JSONObject obj) throws Exception {
+    static public Recon load(JSONObject obj, Map<Long, Recon> reconCache) throws Exception {
         if (obj == null) {
             return null;
         }
         
-        Recon recon = new Recon(obj.getLong("id"));
+        long id = obj.getLong("id");
+        if (reconCache.containsKey(id)) {
+            return reconCache.get(id);
+        }
+        
+        Recon recon = new Recon(id);
         
         if (obj.has("j")) {
             recon.judgment = stringToJudgment(obj.getString("j"));
@@ -225,6 +230,8 @@ public class Recon implements HasFields, Jsonizable {
             }
         }
         
+        reconCache.put(id, recon);
+        
         return recon;
     }
 
diff --git a/src/main/java/com/metaweb/gridworks/model/Row.java b/src/main/java/com/metaweb/gridworks/model/Row.java
index 821f89fc3..8a98ce995 100644
--- a/src/main/java/com/metaweb/gridworks/model/Row.java
+++ b/src/main/java/com/metaweb/gridworks/model/Row.java
@@ -3,6 +3,7 @@ package com.metaweb.gridworks.model;
 import java.io.Writer;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 import java.util.Map.Entry;
 
@@ -152,11 +153,11 @@ public class Row implements HasFields, Jsonizable {
         }
     }
     
-    static public Row load(String s) throws Exception {
-        return s.length() == 0 ? null : load(ParsingUtilities.evaluateJsonStringToObject(s));
+    static public Row load(String s, Map<Long, Recon> reconCache) throws Exception {
+        return s.length() == 0 ? null : load(ParsingUtilities.evaluateJsonStringToObject(s), reconCache);
     }
     
-    static public Row load(JSONObject obj) throws Exception {
+    static public Row load(JSONObject obj, Map<Long, Recon> reconCache) throws Exception {
         JSONArray a = obj.getJSONArray("cells");
         int count = a.length();
         
@@ -165,7 +166,7 @@ public class Row implements HasFields, Jsonizable {
             if (!a.isNull(i)) {
                 JSONObject o = a.getJSONObject(i);
                 
-                row.setCell(i, Cell.load(o));
+                row.setCell(i, Cell.load(o, reconCache));
             }
         }
         
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/CellAtRow.java b/src/main/java/com/metaweb/gridworks/model/changes/CellAtRow.java
index f0e65666c..fa42b01ae 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/CellAtRow.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/CellAtRow.java
@@ -2,9 +2,11 @@ package com.metaweb.gridworks.model.changes;
 
 import java.io.IOException;
 import java.io.Writer;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.model.Cell;
+import com.metaweb.gridworks.model.Recon;
 
 public class CellAtRow {
 
@@ -24,10 +26,10 @@ public class CellAtRow {
         }
     }
     
-    static public CellAtRow load(String s) throws Exception {
+    static public CellAtRow load(String s, Map<Long, Recon> reconCache) throws Exception {
         int semicolon = s.indexOf(';');
         int row = Integer.parseInt(s.substring(0, semicolon));
-        Cell cell = semicolon < s.length() - 1 ? Cell.load(s.substring(semicolon + 1)) : null;
+        Cell cell = semicolon < s.length() - 1 ? Cell.load(s.substring(semicolon + 1), reconCache) : null;
         
         return new CellAtRow(row, cell);
     }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/CellChange.java b/src/main/java/com/metaweb/gridworks/model/changes/CellChange.java
index 4a4ffcad1..307879e0c 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/CellChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/CellChange.java
@@ -3,11 +3,13 @@ package com.metaweb.gridworks.model.changes;
 import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Cell;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 
 public class CellChange implements Change {
     final public int     row;
@@ -53,7 +55,7 @@ public class CellChange implements Change {
         writer.write("/ec/\n"); // end of change marker
     }
     
-    static public CellChange load(LineNumberReader reader) throws Exception {
+    static public CellChange load(LineNumberReader reader, Map<Long, Recon> reconCache) throws Exception {
         int row = -1;
         int cellIndex = -1;
         Cell oldCell = null;
@@ -70,9 +72,9 @@ public class CellChange implements Change {
             } else if ("cell".equals(field)) {
                 cellIndex = Integer.parseInt(value);
             } else if ("new".equals(field) && value.length() > 0) {
-                newCell = Cell.load(value);
+                newCell = Cell.load(value, reconCache);
             } else if ("old".equals(field) && value.length() > 0) {
-                oldCell = Cell.load(value);
+                oldCell = Cell.load(value, reconCache);
             }
         }
         
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/ColumnAdditionChange.java b/src/main/java/com/metaweb/gridworks/model/changes/ColumnAdditionChange.java
index ea3db0d4b..5142d5f81 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/ColumnAdditionChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/ColumnAdditionChange.java
@@ -4,12 +4,15 @@ import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Column;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.Row;
 
 public class ColumnAdditionChange extends ColumnChange {
@@ -92,11 +95,13 @@ public class ColumnAdditionChange extends ColumnChange {
             } else if ("newCellCount".equals(field)) {
                 int newCellCount = Integer.parseInt(line.substring(equal + 1));
                 
+                Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+                
                 newCells = new ArrayList<CellAtRow>(newCellCount);
                 for (int i = 0; i < newCellCount; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        newCells.add(CellAtRow.load(line));
+                        newCells.add(CellAtRow.load(line, reconCache));
                     }
                 }
             }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/ColumnRemovalChange.java b/src/main/java/com/metaweb/gridworks/model/changes/ColumnRemovalChange.java
index fe293c652..eff748d3a 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/ColumnRemovalChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/ColumnRemovalChange.java
@@ -3,12 +3,15 @@ package com.metaweb.gridworks.model.changes;
 import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Cell;
 import com.metaweb.gridworks.model.Column;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.Row;
 
 public class ColumnRemovalChange extends ColumnChange {
@@ -85,11 +88,13 @@ public class ColumnRemovalChange extends ColumnChange {
             } else if ("oldCellCount".equals(field)) {
                 int oldCellCount = Integer.parseInt(line.substring(equal + 1));
                 
+                Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+                
                 oldCells = new CellAtRow[oldCellCount];
                 for (int i = 0; i < oldCellCount; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        oldCells[i] = CellAtRow.load(line);
+                        oldCells[i] = CellAtRow.load(line, reconCache);
                     }
                 }
             }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java b/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java
index 218fb1d9d..cd1e5c361 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java
@@ -5,7 +5,9 @@ import java.io.LineNumberReader;
 import java.io.Serializable;
 import java.io.Writer;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import org.json.JSONException;
@@ -284,6 +286,8 @@ public class DataExtensionChange implements Change {
         
         int firstNewCellIndex = -1;
         
+        Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+        
         String line;
         while ((line = reader.readLine()) != null && !"/ec/".equals(line)) {
             int equal = line.indexOf('=');
@@ -365,7 +369,7 @@ public class DataExtensionChange implements Change {
                 for (int i = 0; i < count; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        oldRows.add(Row.load(line));
+                        oldRows.add(Row.load(line, reconCache));
                     }
                 }
             } else if ("newRowCount".equals(field)) {
@@ -375,7 +379,7 @@ public class DataExtensionChange implements Change {
                 for (int i = 0; i < count; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        newRows.add(Row.load(line));
+                        newRows.add(Row.load(line, reconCache));
                     }
                 }
             }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/MassCellChange.java b/src/main/java/com/metaweb/gridworks/model/changes/MassCellChange.java
index 780842fdd..6160661ac 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/MassCellChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/MassCellChange.java
@@ -3,12 +3,15 @@ package com.metaweb.gridworks.model.changes;
 import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Column;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.Row;
 
 public class MassCellChange implements Change {
@@ -112,9 +115,11 @@ public class MassCellChange implements Change {
             } else if ("cellChangeCount".equals(field)) {
                 int cellChangeCount = Integer.parseInt(line.substring(equal + 1));
                 
+                Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+                
                 cellChanges = new CellChange[cellChangeCount];
                 for (int i = 0; i < cellChangeCount; i++) {
-                    cellChanges[i] = CellChange.load(reader);
+                    cellChanges[i] = CellChange.load(reader, reconCache);
                 }
             }
         }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/MassRowChange.java b/src/main/java/com/metaweb/gridworks/model/changes/MassRowChange.java
index 0257769fb..8b96694cf 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/MassRowChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/MassRowChange.java
@@ -4,11 +4,14 @@ import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.Row;
 
 public class MassRowChange implements Change {
@@ -56,6 +59,8 @@ public class MassRowChange implements Change {
         List<Row> oldRows = null;
         List<Row> newRows = null;
         
+        Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+        
         String line;
         while ((line = reader.readLine()) != null && !"/ec/".equals(line)) {
             int equal = line.indexOf('=');
@@ -68,7 +73,7 @@ public class MassRowChange implements Change {
                 for (int i = 0; i < count; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        oldRows.add(Row.load(line));
+                        oldRows.add(Row.load(line, reconCache));
                     }
                 }
             } else if ("newRowCount".equals(field)) {
@@ -78,7 +83,7 @@ public class MassRowChange implements Change {
                 for (int i = 0; i < count; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        newRows.add(Row.load(line));
+                        newRows.add(Row.load(line, reconCache));
                     }
                 }
             }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/ReconChange.java b/src/main/java/com/metaweb/gridworks/model/changes/ReconChange.java
index 207f64d7f..680b74512 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/ReconChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/ReconChange.java
@@ -6,12 +6,15 @@ package com.metaweb.gridworks.model.changes;
 import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Column;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.ReconStats;
 import com.metaweb.gridworks.model.recon.ReconConfig;
 import com.metaweb.gridworks.util.ParsingUtilities;
@@ -155,9 +158,11 @@ public class ReconChange extends MassCellChange {
             } else if ("cellChangeCount".equals(field)) {
                 int cellChangeCount = Integer.parseInt(value);
                 
+                Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+                
                 cellChanges = new CellChange[cellChangeCount];
                 for (int i = 0; i < cellChangeCount; i++) {
-                    cellChanges[i] = CellChange.load(reader);
+                    cellChanges[i] = CellChange.load(reader, reconCache);
                 }
             }
         }
diff --git a/src/main/java/com/metaweb/gridworks/model/changes/RowRemovalChange.java b/src/main/java/com/metaweb/gridworks/model/changes/RowRemovalChange.java
index d27efc371..23702ce84 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/RowRemovalChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/RowRemovalChange.java
@@ -4,11 +4,14 @@ import java.io.IOException;
 import java.io.LineNumberReader;
 import java.io.Writer;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.Row;
 
 public class RowRemovalChange implements Change {
@@ -90,11 +93,13 @@ public class RowRemovalChange implements Change {
             } else if ("rowCount".equals(field)) {
                 int count = Integer.parseInt(line.substring(equal + 1));
                 
+                Map<Long, Recon> reconCache = new HashMap<Long, Recon>();
+                
                 rows = new ArrayList<Row>(count);
                 for (int i = 0; i < count; i++) {
                     line = reader.readLine();
                     if (line != null) {
-                        rows.add(Row.load(line));
+                        rows.add(Row.load(line, reconCache));
                     }
                 }
             }