seems to be very difficult.
It looks like you should add a romanji and a kanji/hiragana/katakana version.
Usually the japanes address is in one line, the international has some more.
My sources: http://www.upu.int/fileadmin/documentsFiles/activities/addressingUnit/jpnEn.pdf
http://www.upu.int/uploads/tx_sbdownloader/descriptionPostcodesAddressingAddressElementsEn.pdf
http://de.wikipedia.org/wiki/Postadressen_in_Japan
http://en.wikipedia.org/wiki/Japanese_addressing_system
Has someone any experience with sending letters to Japan?
What is the best way to avoid problems?
It looks like you should add a romanji and a kanji/hiragana/katakana version.
Usually the japanes address is in one line, the international has some more.
My sources: http://www.upu.int/fileadmin/documentsFiles/activities/addressingUnit/jpnEn.pdf
http://www.upu.int/uploads/tx_sbdownloader/descriptionPostcodesAddressingAddressElementsEn.pdf
http://de.wikipedia.org/wiki/Postadressen_in_Japan
http://en.wikipedia.org/wiki/Japanese_addressing_system
Has someone any experience with sending letters to Japan?
What is the best way to avoid problems?