A Clear Next Step for Today's Japanese Study
Mastermind learns from every answer you give it. It sees what you get right, what seems to be fading, and what you keep mixing up, then turns that into a clear next step for today's study. Built first for serious JLPT N5 learners with some prior Japanese exposure, with higher levels on the roadmap.
Mastermind Japanese by Jason Kobayashi, built in Tokyo.
What Makes Mastermind Japanese Different
Concept-Level Evidence
Each study item is connected to specific concepts. Answers recorded inside Mastermind update the model's estimates, which supported selectors use when scheduling later practice.
Adaptive Within Each Study Type
Mastermind first chooses a study type. Within each supported type, it uses review timing, prerequisite links, and your in-app answer history to select an item.
Short Session Friendly
Short sessions still add evidence to the model. After time away, scheduled work is recalculated without a missed-day penalty.
How It Works
Show What You've Seen
Take the optional placement check or start studying. Mastermind builds its model only from evidence you create inside the app.
A Reasoned Next Step
The session picks a study type, then adapts item selection within that type. It does not yet run one shared contest across every study type.
See the Estimate, Not a Promise
Concept XP and the readiness band summarize evidence from Mastermind. The band may narrow or widen as new answers arrive.
Current Beta Scope
Built First for Serious N5 Learners
Mastermind is best suited to learners who can already read kana and have some prior Japanese exposure. It is not a from-zero course or a teacher replacement.
- JLPT N5-aligned grammar, vocabulary, and kanji
- Questions, cards, listening, reading, sentence building, optional speaking checks, and N5 kanji handwriting
- Designed to sit alongside classes, textbooks, media, and conversation
Study Stack
Mastermind uses recognition, listening, sentence building, context, and progress tracking so you study the same concepts in more than one way.
What You Train With
The current beta mixes several live study surfaces so you meet the same ideas from different directions.
Sentence Recognition
Adaptive multiple-choice questions check whether you understand the Japanese sentence in context.
Kanji Writing
For supported kanji, draw the character by hand, check recognition locally, and track a cumulative recognition-success count.
Listening
Some cards play the audio first, so you listen and recall before seeing the written Japanese.
Sentence Building
Arrange Japanese pieces into the right order to build a sentence.
Vocabulary Check
A focused vocabulary check asks for a word's reading, meaning, and example usage when that mode selects it.
Concept Map Feedback
Per-concept XP and the Mind Map show the evidence Mastermind has recorded and the model estimates built from it.
Product Facts
- Mastermind Japanese is a Japanese learning web app by Jason Kobayashi in Tokyo.
- The Mind Map organizes connected concepts; supported selectors use answer history from inside Mastermind to adapt practice within each study type.
- The current beta includes a 521-concept JLPT N5-aligned Mind Map and a growing library of curated study content; it does not claim comprehensive N5 coverage.
- Study includes adaptive sessions, listening, optional speaking checks, sentence building, kanji writing, verb study, and vocabulary checks.
- Mastermind is not a from-zero course or teacher replacement; N4 and higher levels are roadmap work, not a current promise.
© 2026 Jason Kobayashi