Sổ Tay Ngữ Pháp Tiếng Nhật is an Android-based educational reference application developed by mocvien.com. The app is an extensive compilation of over 2600 basic Japanese grammar patterns, from N5 to N1 levels.

The app has an intuitive search function that allows users to find the grammar patterns they need quickly. Additionally, users can mark the grammar patterns they have already studied and revisit them later. The app is also designed to keep track of the user's search history, making it easier for them to pick up where they left off.

Each grammar pattern is numbered, so users can easily reference them while studying. The search function also features the use of wildcards such as * and ? to find specific grammar patterns. Overall, Sổ Tay Ngữ Pháp Tiếng Nhật is an excellent tool for anyone looking to learn Japanese grammar, whether they are beginners or advanced learners.