# KotsuKotsu: JLPT Vocabulary — Kana to N1, before you forget

> Spaced repetition Japanese vocabulary learning app for JLPT levels. (iPhone/iPad app by JJangJJangE.)

- Source: https://appshunter.io/ios/app/kotsukotsu-jlpt-vocabulary/id6802480913 (this page in markdown: same URL + `.md`)
- Developer: [JJangJJangE](https://appshunter.io/developer/1875805903)
- Category: Education, Reference
- Price: Free
- Age rating: 4+
- Requires: iOS 16.4 · 65 MB
- Languages: American English, French (France), Indonesian, Korean, Chinese (Simplified, China), European Spanish, Thai, Chinese (Traditional, Taiwan), Vietnamese
- Released: 2026-08-24
- Data updated: 2026-10-25
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/kotsukotsu-jlpt-vocabulary/id6802480913/reviews.md

## What is KotsuKotsu?

Ever shelved a vocabulary book with the first thirty pages black with notes and the rest still spotless?

The problem isn't willpower. It's order. Nobody can tell by feel what to review and when. KotsuKotsu is a Japanese vocabulary app that works it out for you: 18,557 words from hiragana to JLPT N1 and beyond. All you have to do is today's cards.


“What should I study today?”

The app picks for you. It starts with the 208 hiragana and katakana, then runs through JLPT N5, N4, N3, N2, and N1 to words beyond the levels, in Days of 50 flashcards. Open the app and today's cards are waiting.


“I saw it once. Why didn't it stick?”

That's how memory works.

In 1885, Hermann Ebbinghaus drew the forgetting curve: two thirds or more of something new is gone within a day. But recall it right before you forget, and the curve flattens. Seeing a word once a day for ten days beats seeing it ten times in one day. This is the spacing effect, confirmed by a 2006 meta-analysis of 317 experiments from 184 papers.


“So when does it ask me again?”

The moment your chance of remembering drops to 90%.

KotsuKotsu draws a forgetting curve for every card and asks again just as the memory starts to blur. Each right answer pushes the next review out: a new word comes back in 10 minutes, a familiar one in a few days, and one you truly know in a few months. Miss it and the gap shrinks.

So your time goes to the words you don't know yet, not the ones you do, and the same 30 minutes leaves you with more.

KotsuKotsu runs on FSRS, the spaced repetition algorithm built into Anki, refined on 700 million reviews from 10,000 real learners.


“How much do I know right now?”

Every word has a temperature: where it sits on its forgetting curve, turned into a color. A word you just learned is a warm green, one you haven't seen in a while cools to orange, and one you've missed three or more times sinks to red. Scroll a word list and the gaps show at a glance.


“How far have I come?”

Track your streak and accuracy, look back on a heatmap, and see when you'll finish at your current pace.


“Why no example sentences?”

Because they don't help you memorize words.

For every feature, we asked: “Could you still memorize words without it?” Example sentences, rankings, friend lists, and logins didn't make the cut. The card holds the kanji, reading, meaning, part of speech, and word origin. That's all.


“Why no rankings?”

Because someone else's pace shouldn't become your yardstick.

New words per day, the review limit, target retention, when your day starts: you decide all of it.

There are no notifications either. Nagging alerts only make you feel chased, and an app you open that way doesn't last.

There are no accounts. Your history stays on your device, and you can export it to move to a new one.


And more

· Audio plays automatically when you flip a card
· Choose from four voices, two female and two male, and download them to listen offline
· Search by word, reading, or meaning, even in katakana or romaji
· Save the words you like and add your own notes
· Words you're forgetting and words you often miss gather in their own lists
· Words spelled the same but read differently (like 行く: いく and ゆく) link to each other in word details
· In each Day, blur readings or meanings, shuffle, or see the words you remember least first
· Menus and word meanings also come in Korean, Chinese (Traditional and Simplified), Vietnamese, Thai, Indonesian, Spanish, and French
· Browse the same vocabulary as cards at kotsu-kotsu.app/en, with history kept separate from the app
· Light and dark themes, with background effects and blur you can turn off


It's made for complete beginners starting from hiragana, test takers organizing JLPT words by level, and working adults learning Japanese on their own, without classes.


Smart is the app's job. Steady is yours.
Just finish today's cards.

## Key features

- Spaced repetition algorithm (FSRS)
- 18,557 Japanese vocabulary words
- JLPT N5 to N1 coverage
- Daily flashcard scheduling
- Visual progress tracking (heatmap, temperature)
- Offline audio playback

## Is KotsuKotsu safe?

Not enough ratings yet to assess KotsuKotsu.

## Is KotsuKotsu legit?

KotsuKotsu: JLPT Vocabulary appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for KotsuKotsu is 65 out of 100 points across 7 verification signals from App Store and developer data.

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/kotsukotsu-jlpt-vocabulary/id6802480913/reviews.md

### 5/5 — ‘가’ 발음 오류

*2026-10-05*

정말 잘 쓰고 있습니다!!
다름이 아니라 が와 ガ 발음이 ‘가’가 아닌 ‘라’로 나와서 문의드립니다..!!

**Developer response:** 안녕하세요, 리뷰 남겨 주셔서 감사합니다! 확인해 보니 が·ガ 녹음은 '가'로 되어 있지만, 하루카 목소리는 g 소리를 부드럽게 내는 편이라 말씀하신 대로 낱자로 들으면 '라'에 가깝게 들릴 수 있어요. 설정의 「목소리」에서 아오이·타쿠미·리쿠로 바꾸시면 '가'로 더 또렷하게 들으실 수 있습니다. 다음 업데이트에서는 학습 중에도 카드 아래 톱니 버튼에서 목소리를 바로 바꾸실 수 있도록 개선해 보겠습니다!

### 4/5 — 앱은 정말 좋은거같은데 소리가 안나와요 ㅠㅠㅠ

*2026-09-19*

정말 잘 쓰고있습니다 ㅠㅠ
따로 저장할필요도 없이 단아만 외우면 되서 좋은데 소리가 안나와서 외우기가 빡세네요 빨리 고쳐주세요ㅠㅠ

**Developer response:** 안녕하세요, 코츠코츠 개발자입니다. 좋게 봐 주셔서 감사하고, 소리 문제로 불편을 드려 죄송합니다.

확인해 보니 발음 서버는 정상이었고, 아이폰 벨소리를 무음으로 두면 발음도 함께 무음이 되는 버그가 있었습니다. 발음은 벨소리와 무관하게 나와야 하는 소리라 무음 모드에서도 재생되도록 고쳤고, 1.1.5 업데이트로 나갈 예정입니다. 업데이트 전까지는 측면 스위치를 벨소리로 두시면 소리가 납니다.

발음 목소리와 볼륨은 오른쪽 위 톱니로 여는 설정 화면 아래쪽에서 바꾸실 수 있고, 발음을 미리 받아 두면 인터넷 없이도 들을 수 있습니다.

업데이트 뒤에도 소리가 나지 않으면 contact@kotsu-kotsu.app 으로 기종과 iOS 버전, 무음 스위치 상태, 어느 화면에서 소리가 나지 않는지 알려 주세요. 바로 살펴보겠습니다.

## Frequently asked questions about KotsuKotsu

### What is KotsuKotsu's learning methodology?

KotsuKotsu utilizes the spaced repetition system (SRS), specifically the FSRS algorithm, to schedule vocabulary reviews. This method is scientifically proven to enhance long-term memory retention by presenting words at optimal intervals before you forget them.

### How does KotsuKotsu track my learning progress?

The app assigns a 'temperature' to each word, visually indicating its position on your personal forgetting curve. You can also view a heatmap of your study activity and track your streak and accuracy to monitor your overall progress.

### Does KotsuKotsu offer JLPT certifications?

KotsuKotsu is designed to help you memorize vocabulary relevant to the JLPT exams (N5 through N1), but it does not offer official certifications. Its focus is on building your vocabulary knowledge base for the test.

### Can I use KotsuKotsu offline?

Yes, KotsuKotsu supports offline audio playback for vocabulary words. You can download the audio for four different voices to listen to words without an internet connection.

### How many vocabulary words does KotsuKotsu contain?

KotsuKotsu includes a comprehensive database of 18,557 Japanese vocabulary words, covering everything from hiragana and katakana to words beyond the JLPT N1 level.

### Is KotsuKotsu suitable for beginners?

Absolutely. KotsuKotsu starts with the basics, including hiragana and katakana, and progresses through all JLPT levels. The app's intelligent scheduling makes it effective for learners at any stage.

### How often is KotsuKotsu updated?

The latest version of KotsuKotsu is 1.2.1, which was last updated on October 5, 2026. Updates typically include refinements to the learning algorithm and vocabulary database.

### What devices does KotsuKotsu support?

Currently, KotsuKotsu is available for iPhone devices. Future platform expansions may be considered based on user demand and development resources.

## Version history (last 5 releases)

### 1.2.2 — 2026-10-10

- You can now change the voice right from the gear on the study screen. Pick one and the current word plays in that voice.
- Word lists no longer cut off words or readings. A long reading moves to the next line, and meanings show up to three lines.
- Hide readings and Hide meanings now cover answers with clean bars instead of a blur, on the kana charts too.
- Fixed pronunciation sometimes not playing when you reveal several hidden rows in a row.
- Tidied up line breaks on narrow screens and the message for empty collections.

### 1.2.1 — 2026-10-05

- The App Store page now lists all nine languages KotsuKotsu supports. Nothing has changed inside the app.

### 1.2.0 — 2026-10-04

- Now in English, from the menus to the word meanings. You can also choose Korean, Chinese (Traditional and Simplified), Vietnamese, Thai, Indonesian, Spanish, or French in Settings → Language.
- Study settings now have their own button on the Study tab, just left of the gear. Change new cards per day, the daily review limit, and target retention right there.
- Hide now blurs instead of covering. Readings, meanings, and romaji blur out in word lists and on the kana charts.
- You can now search in romaji: ringo finds りんご, and ramen finds ラーメン even without the long vowel.
- Moved 1,028 words to the JLPT levels they belong in, fixed reading errors, and redid the audio for some words. Moved words keep their study history, saved status, and notes.
- Fixed dates getting cut off in Upcoming reviews.

### 1.1.6 — 2026-09-25

- 카드 앞면에서 연 단어 시트의 가려진 읽기나 뜻을 누르면 바로 볼 수 있어요.
- 암기 화면에서 돌아왔을 때 학습 탭이 비어 보이던 문제를 고쳤어요.
- 카드를 빠르게 넘기면 발음이 가끔 나오지 않던 문제를 고쳤어요.

### 1.1.5 — 2026-09-21

- 아이폰이 무음 모드일 때도 발음이 들리도록 고쳤어요.

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All apps by JJangJJangE: https://appshunter.io/developer/1875805903

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-25.*