As part of our in-house education service, we have created an app called Samurai that allows you to improve your Japanese language skills at any time with numerous multiple-choice questions.
There are approximately 10,500 questions in the database, divided into 5 levels: N1, N2, N3, N4, and N5.
When you get bored with just answering questions, you can use the game function to make studying Japanese more fun.

Reference URL: https://play.google.com/store/apps/details?id=com.kaopiz.japanesefight