Finally the updates have come through! The updated apps (Kanji Wordsearch full version and lite version) and a free version were finally released on April 8th.
Please note - Crashing on startup has been reported by a few people updating, but it has always been resolved by deleting the app (on device and iTunes), doing a 'hard reset' (by holding the home button plus top power button for 5 seconds), and turning back on and downloading again (no need to pay again) and re-installing the app.
If your phone has been bit erratic, it may be a good idea to do a full restore (resets phone to factory settings, backing up content on iTunes) see _http://support.apple.com/kb/ht1414
Oliver Rose in Kansai, Japan