About Inku

Inku is a Japanese learning app that teaches kana, kanji, vocabulary and phrases with flashcards, pronunciation audio and spaced review, for adults who want a short, steady study routine on iPhone or in a web browser.

You open it, learn a few new words, review the ones that are due, and close it knowing exactly what you studied. Everything below explains how that works, who it suits, and who builds it.

What Inku does

Prepared Japanese decks

You can start studying in the first minute, because the decks are already written. There are vocabulary decks for every JLPT level from N5 to N1, everyday topic decks such as food, travel and counting, and three phrase packs for casual, polite and travel Japanese. The JLPT does not publish official word lists, so these are curated study decks rather than a complete exam list.

Hiragana and katakana

Reading starts with kana, so Inku teaches both scripts first, with audio for every character. The course covers the voiced and combined sounds as well as the basic characters, and the kana chart plays any character you tap.

Kanji lessons

Kanji has its own course. Each lesson teaches five kanji with their meanings, readings, a memory cue where one helps and a sample word, and then asks you to recall them. The course covers 960 kanji from N5 to N1.

Lessons that teach before they test

A lesson shows you five new words or phrases with the Japanese, the reading, the meaning and the audio, and then asks you to recall the same five. You meet each word properly before it ever appears as a question.

Spaced review

After a lesson, each word joins your reviews. Inku schedules them with FSRS, a spaced-repetition algorithm that brings a word back sooner when you miss it and later when you remember it, so your time goes to the words you are about to forget. You answer Again or Got it, and a word you already know can be marked Too easy.

A personal Library and your own cards

Save any word or phrase to your Library and find it again in Japanese or romaji. When you meet a word in class, in a show or in a conversation, make your own card for it and group cards into your own decks, so the Japanese you actually meet sits beside the decks Inku provides.

What makes Inku different

Content and scheduling come together

General flashcard tools such as Anki give you a powerful scheduler and leave the Japanese to you. Inku supplies the Japanese and runs the schedule, so you spend your time studying rather than building decks. The tradeoff is less control. Inku vs Anki explains when each approach fits.

Japanese only

Every deck, lesson and design decision in Inku is for Japanese. The app teaches the writing system directly, from kana to kanji, instead of treating Japanese as one course in a multi-language template.

A quiet routine

Inku has no ads, leagues, hearts or leaderboards. A session ends when its cards are done, and your streak and progress are there to encourage you, not to rank you against anyone else.

Clear about what it does not teach

Inku does not teach grammar, check your pronunciation, or give you long listening and reading practice. We say so plainly on our comparison pages, and we point you to tools that fill those gaps.

Who Inku is for

Inku is designed for these learners:

• Complete beginners who need to learn hiragana and katakana before anything else.
• Learners working toward a JLPT level who want vocabulary and kanji organized from N5 to N1.
• Returning learners who want to restart at their level without rebuilding a deck.
• Intermediate learners who want a prepared vocabulary and kanji core beside their reading, listening and grammar study.
• Adults with a few minutes a day who prefer a calm routine to a game.

This describes who Inku is built for. We do not publish user counts or testimonials on this page.

The person behind Inku

Inku is made by Bao Hua. Bao grew up in Canada in a Vietnamese family, and his partner is Japanese, so learning Japanese was personal from the start. It was also frustrating: the flashcard tools he tried felt clumsy and got in the way of the language. So he built the app he wanted to use, learning to work with coding agents as he went, and that app became Inku.

Bao studied finance, but games and design have always drawn him in, and Inku is where those interests meet. He is obsessed with self-improvement, which makes learning a language a natural fit. Away from the app, he plays basketball and volleyball and is addicted to tennis. He tells more of the story in I built the Japanese app I wanted.

Inku is an independent product that Bao runs as a sole proprietor from Calgary, Alberta, not a team inside a larger company. He answers support email to app@inkujapanese.com himself. You can also find him on X as @baothepenguin, and his author page is here.

How Inku works

Getting started

On the web, you can take an introductory lesson before you sign up. To keep studying, you create an account and start Inku Pro. On iPhone, you download the app from the App Store and subscribe there; the iPhone app does not need an account.

Choosing what to study

Open Decks to choose a JLPT level, a topic or a phrase pack, or open the Kana or Kanji course. When you start, Inku asks about your level so the first lessons match what you already know.

Learning and reviewing

Each lesson teaches five items and then quizzes them. After that, Home shows the reviews that are due, and FSRS decides when each item comes back. Kana and kanji have their own review alongside your words and phrases.

Getting help

The help center answers common questions about studying, billing and your data. For anything else, email app@inkujapanese.com or use the contact page. On the web, signed-in learners can also report a problem with a card from the card itself.

Key facts

Product

Inku (App Store name: Inku: Japanese Flashcards)

Category

Japanese language-learning app with flashcards and spaced repetition

Founder

Bao Hua

Operator

Bao Hua, sole proprietor, Calgary, Alberta, Canada

Website

inkujapanese.com

What it teaches

Hiragana, katakana, kanji, JLPT N5–N1 vocabulary, topic vocabulary and phrases

Review method

Lessons of five items, then FSRS spaced review

Platforms

iPhone (iOS 18 or later) and web browsers. No Android app yet.

iPhone release

June 2026 on the App Store

Business model

Inku Pro subscription. No ads.

Support

app@inkujapanese.com

Founder on X

@baothepenguin

Frequently asked questions

Where to go next: How to learn Japanese from scratch · Compare Inku with other apps · The Inku Library