About JLPT Mastery
A free JLPT reference and an adaptive practice engine built around the mistakes you actually make.
What this is
JLPT Mastery is a study tool for the Japanese-Language Proficiency Test, covering all five levels from N5 to N1. It has two halves. The public half is a free reference: vocabulary lists by theme, grammar explanations with example sentences, kanji tables, level guides, and full-length mock papers. The private half is an adaptive practice engine that tracks what you personally keep getting wrong and builds sessions around it.
Why it exists
Most JLPT tools measure whether you got a question right. That tells you a percentage and not much else. The thing that actually costs marks in the exam is mixing up two specific items that look or sound alike, and a general accuracy score cannot see that. This site was built around recording which wrong answer you chose, not just that you were wrong, because that is the piece of information that makes practice targeted instead of repetitive.
How the practice engine works
Every word and grammar point you attempt is tracked through a set of mastery states. Answer correctly twice in a row and an item is promoted to mastered. Miss a mastered item and it drops back for rechecking. Sessions are then assembled from your own state: mostly items you are weak on, a few mastered ones to confirm they have stuck, and any confusion pairs you have built up. None of this logic runs in your browser, so the progression cannot be gamed by refreshing.
Where the content comes from
Vocabulary and grammar lists are compiled from past-exam analysis, standard textbooks, and community-maintained level lists, because the Japan Foundation has not published official vocabulary or grammar lists since 2010. Grammar explanations and confusion-pair explanations are generated with Google Gemini and reviewed before publication. Kanji readings and stroke counts come from openly licensed character data. Exam scoring figures and pass rates on this site are the official published numbers from the Japan Foundation and JEES.
What it is not
JLPT Mastery is an independent study tool. It is not affiliated with, endorsed by, or connected to the Japan Foundation or Japan Educational Exchanges and Services, who own the JLPT trademark and run the exam. Nothing here is an official past paper. The mock exams are original papers written to the real format and timing, not reproductions of exams that have been sat.
How it is funded
Practice, mastery tracking and confusion drills are free to use with an account, and the reference pages are free without one. The public reference pages carry advertising to cover hosting and data costs. Ads are deliberately kept off the mock exam and practice screens, because an advert next to a timed question is a worse product.
Who builds it
The platform is built and maintained by a small team. You can see who contributes on the contributors page, and anyone is welcome to help via contribute. For corrections, questions, or anything else, the contact page reaches us directly. If you find a factual error in an explanation, we would rather hear about it than not.