Jouyou Kanji (常用漢字) Widget is a free educational Android app developed by ChaiDEV. It is a comprehensive learning tool for Japanese Kanji, consisting of 2136 Kanji issued in 2010, officially announced by the Japanese Ministry of Education. The app includes Kanji with On-yomi (Chinese sound) and Kun-yomi (Japanese sound), and Kanji for all JPTS exam levels with meaning.

The app also features Romanji/Hiragana-Katakana and Japanese Kun-yomi pronunciation when opening a Kanji, which requires an online connection. Additionally, the app is free of spams/viruses. Overall, Jouyou Kanji (常用漢字) Widget is an excellent resource for anyone looking to learn and expand their knowledge of Japanese Kanji.

However, it is worth noting that the app is not a standalone course and is best used as a supplement to other learning resources. It would be helpful if the app included more interactive features or exercises to reinforce learning. Nevertheless, Jouyou Kanji (常用漢字) Widget is a highly recommended app for anyone interested in learning Japanese Kanji.