app-misc/anki can use mecab-python and mecab-ipadic to automatically convert between Kanji and kana characters. It does not work properly unless mecab-ipadic is configured with: --with-charset=euc-jp Reproducible: Always
The anki author talks about this issue here: http://groups.google.com/group/ankisrs/browse_thread/thread/e15f8d4cbd2ed98f I have verified that this is indeed the case, and that the resolution proposed in my initial comment resolves the problem.
Please emerge app-dicts/mecab-ipadic without unicode useflag like: $ USE=-unicode emerge app-dicts/mecab-ipadic (for temporary) or $ echo "app-dicts/mecab-ipadic -unicode" >> /etc/portage/package.use $ emerge app-dicts/mecab-ipadic