diff --git a/massgen.py b/massgen.py
index 8bb7160..eb6b00b 100644
--- a/massgen.py
+++ b/massgen.py
@@ -43,6 +43,18 @@ def massseriesgen(series,massindex):
     skel.headerwrite(thefile,"mass")
     content = open(thefile,"a")
     content.write("<h1>" + series + "</h1>\n<p><a href=\"/mass\">back to mass decks page</a></p>\n<p>")
+    themassdecks = []
+    for card in massowned[series]:
+        themassdecks.append(card[:-2])
+    themassdecks = sorted(list(dict.fromkeys(themassdecks)))
+    massmastered = []
+    for deck in themassdecks:
+        if tcgcore.deckmastered(deck):
+            massmastered.append(deck)
+    if len(massmastered) > 0:
+        for deck in massmastered:
+            content.write("<img src=\"/decks/" + deck + "/master.gif\" title=\"mastered " + deck + "\">")
+        content.write("</p><p>")
     for card in massowned[series]:
         content.write(tcgcore.printcard(card))
     content.write("</p>\n")