JLPT Locker is an educational app designed for Android users to help learn and memorize over 8,000 Japanese characters, categorized according to the Japanese Language Proficiency Test (JLPT) levels from N5 to N1. It combines flashcards and quizzes to facilitate effective learning through repetition and assessment. Users begin with N5 characters and progressively advance to more complex levels as they demonstrate their familiarity with each character.

The app features a unique depth assessment system that adjusts the learning process based on the user's performance. Correct answers reduce the depth of a character, while incorrect answers increase it, ensuring that users focus on challenging characters until they are mastered. This adaptive learning approach allows both beginners and advanced learners to tailor their study experience, making JLPT Locker a versatile and effective tool for mastering Japanese characters.