diff --git a/proto/collection.proto b/proto/collection.proto
index 5d14866..d94b6fc 100644
--- a/proto/collection.proto
+++ b/proto/collection.proto
@@ -148,6 +148,11 @@ message Card {
      */
     CARD_TYPE_DISPLAY = 5;
     CARD_TYPE_MOSTVIEWED = 6;
+    /**
+    * An empty card is used to indicate an empty space so that the native
+    * client do not stretch the previous card to occupy the space
+    */  
+    CARD_TYPE_EMPTY = 7;
   }
   CardType type = 1;
   Article article = 2;
diff --git a/proto/proto.lock b/proto/proto.lock
index 2b6ad86..43486d6 100644
--- a/proto/proto.lock
+++ b/proto/proto.lock
@@ -53,6 +53,10 @@
               {
                 "name": "CARD_TYPE_MOSTVIEWED",
                 "integer": 6
+              },
+              {
+                "name": "CARD_TYPE_EMPTY",
+                "integer": 7
               }
             ]
           },