Inku vs Rocket
Inku vs Rocket Japanese for Japanese
Rocket Japanese is a one-time-purchase audio-and-text course. Inku is a calm subscription flashcard app for iPhone. Course vs tool.
Intro
Rocket Japanese is one of the few major courses still offered as a one-time purchase rather than a subscription. It bundles audio lessons, written lessons, and culture notes across three levels. Inku is the opposite shape: a small, focused flashcard app you subscribe to. Buy a course, or rent a tool.
When Inku is the better pick
- You want a calm daily ritual, not a 30-60 minute lesson. Rocket Japanese lessons run long. Inku's session is finite — 10-15 minutes for most adults.
- You want a modern spaced-repetition scheduler. Rocket has built-in flashcard tools but uses a basic interval system. Inku uses FSRS.
- You're focused on retention, not lessons. Rocket teaches new material. Inku makes the material you already know stick. Different jobs.
When Rocket is the better pick
- You hate subscriptions and want to own your course. Rocket is one of the few major Japanese courses sold as a permanent license. If subscription fatigue is real for you, Rocket fits.
- You want structured grammar lessons. Rocket has a real Japanese grammar curriculum across three levels. Inku does not teach grammar directly.
- You want native + non-native instructor explanations. Rocket's Japanese hosts include both native speakers and an English-speaking guide who explains pitfalls. Inku has no instructor at all.
Feature-by-feature
Sources and pricing
Pricing last checked: April 28, 2026. Prices can vary by country, platform, checkout, tax, and promotion.
| Feature | Inku | Rocket | Best fit |
|---|---|---|---|
| Format | Flashcards + audio | Audio + text lessons + flashcards | |
| Daily commitment | 10-15 min | 30-60 min/lesson | |
| Grammar lessons | None | Full curriculum | |
| SRS algorithm | FSRS | Basic interval | |
| Payment model | Subscription | One-time per level | |
| Total cost over 3 years | ~$210 | $300-600+ across 3 levels | |
| Platform | iPhone | Web + iOS + Android |
Inku's favor · Rocket's favor · roughly even
The honest take
Rocket is the right choice if you want structured grammar lessons you own forever and the subscription model bothers you. Inku is the right choice if you want a small daily app that makes Japanese stick. Some adults run Rocket as their morning lesson and Inku as their afternoon review — the combination works.
Verdict
Use Rocket if: you want a one-time-purchase course with grammar. Use Inku if: you want a subscription tool focused on daily vocabulary retention.
Rocket for the lesson, Inku for the retention.
Affiliation note
Inku is not affiliated with Rocket Japanese. This comparison uses public product pages, app listings, and help documents where available.
Common questions
Is Rocket Japanese still updated?+
The course has been updated periodically since 2004. New audio recordings have been added, but the core curriculum is mature rather than rapidly evolving.
Does Rocket Japanese teach kanji?+
Lightly, mostly through context inside vocabulary. For systematic kanji, you'd still pair with WaniKani or similar.
Is one-time-purchase actually cheaper long-term?+
Depends on study horizon. Three Rocket levels at full price runs $300-$600. Three years of Inku runs $210. If you only ever want Level 1 of Rocket, it's cheaper than three years of any subscription.
See more comparisons: all comparison pages. Or start with the full learning roadmap.