Kana Karate from Aztecbyte is an educational game for people who want to learn English, Spanish, German, Portuguese, French, Italian vocabulary and especially the Japanese writing system. The system itself is complicated - there is Hiragana and Katakana (together called Kana) and Kanji. Learning it is all about drill. There's plenty of apps that can help you learn it, but I can say that this one is definitely the most fun!