If you're learning Japanese, then you'll probably appreciate any help you can get from your Mac.
iKanji is the most comprehensive study tool available on the Mac and will be of use to any serious Japanese student. Kanji is beautifully presented in a series of tests meant to improve and bolster your Japanese learning course (but not replace it). iKanji involves three multiple choice tests - Kanji Meanings, Kanji Readings and Kanji Writing.
iKanji makes it very easy to test yourself on a specific subset of kanji, just press the practice button on the kanji you want to test and then pick the practice set in any of the test modules. In addition, there are over 16,000 example words are also provided in kanji and kana with their meaning in English.
IKanji is a beautifully presented and designed complement for anyone wanting to improve their Japanese.