Merge pull request bitcoin#130 from bip39JP/master

BIP39: Clarify necessity for ideographic spaces.

Author: laanwj

bip-0039/bip-0039-wordlists.md

@@ -11,10 +11,12 @@
 
 ###Japanese
 
-1. Users will most likely separate the words with UTF-8 ideographic space.  
-(UTF-8 bytes: 0xE38080) When generating the seed, normalization as per the spec will
-automatically change these into normal ASCII spaces. Depending on the font, displaying the
-words should use the UTF-8 ideographic space if it looks like the symbols are too close.
+1. **Developers implementing phrase generation or checksum verification must separate words using ideographic spaces / accommodate users inputting ideographic spaces.**  
+(UTF-8 bytes: **0xE38080**; C/C+/Java: **"\u3000"**; Python: **u"\u3000"**)  
+However, code that only accepts Japanese phrases but does not generate or verify them should be fine as is.
+This is because when generating the seed, normalization as per the spec will
+automatically change the ideographic spaces into normal ASCII spaces, so as long as your code never shows the user an ASCII space
+separated phrase or tries to split the phrase input by the user, dealing with ASCII or Ideographic space is the same.
 
 2. Word-wrapping doesn't work well, so making sure that words only word-wrap at one of the  
 ideographic spaces may be a necessary step. As a long word split in two could be mistaken easily