diff --git a/errata.html b/errata.html
index 9dee8ae..0700eb7 100644
--- a/errata.html
+++ b/errata.html
@@ -134,6 +134,12 @@ pre {
     (Thanks to Mitsuteru Sawa, 2015-12-07.)
   </p>
 
+  <p>
+    <b>p.347, Exercise 12.8</b>: for "like <code>json.Marshal</code>",
+    read "like <code>json.Unmarshal</code>".
+    (Thanks to chai2010, 2016-01-01.)
+  </p>
+
   <p>
     <b>p.362</b>: The <code>gopl.io/ch13/bzip</code> program
     does not comply with the