diff --git a/lib/commands.py b/lib/commands.py
index 731d40d3..a2bfc9d4 100644
--- a/lib/commands.py
+++ b/lib/commands.py
@@ -134,7 +134,7 @@ class Commands:
     def make_seed(self, nbits, custom_entropy, language):
         from mnemonic import Mnemonic
         s = Mnemonic(language).make_seed(nbits, custom_entropy)
-        return s
+        return s.encode('utf8')
 
     def check_seed(self, seed, custom_entropy, language):
         from mnemonic import Mnemonic
diff --git a/lib/mnemonic.py b/lib/mnemonic.py
index aa0a78fe..9ca8d5d7 100644
--- a/lib/mnemonic.py
+++ b/lib/mnemonic.py
@@ -37,6 +37,8 @@ class Mnemonic(object):
             filename = 'english.txt'
         elif lang[0:2] == 'pt':
             filename = 'portuguese.txt'
+        elif lang[0:2] == 'ja':
+            filename = 'japanese.txt'
         else:
             filename = 'english.txt'
 
@@ -48,7 +50,7 @@ class Mnemonic(object):
             line = line.strip(' \r')
             assert ' ' not in line
             if line:
-                self.wordlist.append(line)
+                self.wordlist.append(line.decode('utf8'))
         print_error("wordlist has %d words"%len(self.wordlist))
 
     @classmethod