Mastermind Is the Adaptive Mind for Learning Japanese
Mastermind maps what you know, finds what needs practice, and keeps each session focused on the next useful thing. Current beta: JLPT N5 with the Mind Map, adaptive practice, kanji writing, listening-first cards, vocab, and personal decks. More content coming soon.
Mastermind Japanese is an app built by Jason Kobayashi in Tokyo.
What Makes Mastermind Japanese Different
Concept-Level Tracking
Each study item is connected to specific concepts. Your answers update those concept strengths, so weak or uncertain areas can come back at a useful time.
Practice That Meets You
Mastermind uses the Mind Map to decide whether to review, repair, or introduce a nearby next concept, so practice stays close to what you are ready to learn next.
Short Session Friendly
Short sessions still count. Each answer helps Mastermind decide what to review, repair, or stretch next.
How It Works
Start Learning Right Away
Answer a few questions. Mastermind estimates your current concept strengths.
Practice What You Are Ready For
Questions adapt to what you know and what you are ready to learn next.
Track Readiness Across the Concepts You've Practiced
See your concept progress over time and keep momentum toward practical Japanese fluency.
Beta Access
Join the Beta
Live in BetaTry the current beta build with full access to current JLPT N5 content.
- Adaptive study engine
- Full access to current JLPT N5 content
- Session progress tracking
Practice Stack
Mastermind uses recognition, listening, sentence building, context, and progress tracking so you can practice 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 Practice
For supported kanji, draw the character by hand, check recognition locally, and build a lifetime correct count.
Listening-First Cards
Some warm review cards start with audio, asking you to listen before revealing the written Japanese.
Tap-to-Build Sentences
When the pieces are ready, sentence-builder cards let you tap Japanese chunks into the right order.
Vocab Card Review
Flashcards reinforce Japanese, reading, meaning, and example usage when a word needs more direct attention.
Concept Map Feedback
Per-concept strength tracking and the Mind Map show what is opening up, what is weak, and where to study next.
Product Facts
- Mastermind Japanese is a Japanese learning web app built by Jason Kobayashi in Tokyo.
- The Mind Map organizes Japanese into connected concepts, then adapts practice based on your progress with each one.
- The first live version focuses on JLPT N5 with 247 Mind Map concepts and 688 curated study items.
- Practice includes adaptive study, listening cards, tap-to-build, kanji and verb practice, and vocab flashcards.
- The current beta is free and open now.
© 2026 Jason Kobayashi