Simple Kana Cards is a simple learning app for Hiragana and Katakana (incl. diacritics).
To learn more efficiently, you are not limited to blocks from the alphabets but you can also choose from groups with geometrically similar letters. In addition, the letters asked in the test adapt to your performance: the more often you associate a letter wrongly, the more likely it gets another turn.
In the learn card mode you can swipe over the screen to move to the next or previous letter and you can turn the card with a tap.
Feel free to send mails about errors or feedback in general to learn-kana (ät) fantasymail.de.