This is essentially a flash card type system that should be used with some other program or book. I have always felt that the best way to learn kanji is to learn how to write them and this app forces you to do so (enable raw squigs for the best practice). The subscription is not free but if you are determined and are willing to put the time into this app then there is no better tool out there as far as Ive seen.
quartzimer about Skritter Japanese