Comparison

Challenge with Erin vs Juken

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Challenge with Erin

This app offers interactive lessons and quizzes to help users learn Japanese vocabulary, grammar, and culture. It features engaging games, manga-based dialogues, and cultural trivia to make studying enjoyable and effective. Track your progress, earn certificates, and compete with others on leaderboards.

Highlights
  • Interactive vocabulary games
  • Manga-based dialogue practice
  • Japanese culture quizzes
  • Progress tracking and points system
  • Weekly tests with certificates
  • Mini dictionary with Romanization
Features
Read full description

-Contents and how to use the app- Study and enjoy yourself. Study section In the study section (‘Let’s Try’) there are four maps: spring, summer, autumn and winter, and you start with spring in the same way as Japanese schools start in spring. Contents: ・KOTOBA1 remember words through a game where you match cards with the same pictures ・KOTOBA2 make sentences by matching illustrations of verbs with cards of vocabulary often used with those verbs ・KOTOBA3 choose illustration cards with the same meaning as Japanese character cards and match the cards ・MANGA become characters in a manga, choose the appropriate lines from the choices you are given, and read them out loud ・BUNKA deepen your understanding of Japan through a quiz about Japanese culture and society ・STAGE TEST a review test of what you studied at each stage. 20 multiple choice questions each with four options -Challenge yourself! - Test section There are 16 tests altogether in the test section (‘TEST’). You can take eight of these any one week. The questions change each week. Challenge yourself and check which Japanese vocabulary and words you remember and know with this test. Once you finish the tests, you will be issued with a certificate of results that includes your name. If your percentage of correct answers exceeds 80%, you receive a pass certificate that includes a medal (illustration)! -A variety of features- ・KOTOBA LIST A mini dictionary where you can find all the vocabulary and expressions that appear in the app. Each of the words that you answered that you had remembered have a check mark next to them. In the list each word is also written in Roman alphabet and hiragana/katakana, and there is a translation of the word’s meaning to enable you to study Japanese characters. ・STATUS Every time you log in to the study section and study, you receive 100 points, and when you take a stage test, that score is added as points. You can see the results of your study to date, including your overall points, your weekly points (total points from the most recent Monday to Sunday), the number of words you have remembered so far, the number of stages you have cleared, and the number of tests you have passed. ・RANKING Displayed here is the overall point ranking of all learners using this app and the number of stages they have cleared, as well as your own overall points and number of stages cleared. ・HONIGON’S CAMERA When you clear the stage test of each stage in the study section, HONIGON’S CAMERA starts up. For each stage various different frames (background illustrations) are displayed, and you can take a ‘celebratory photograph’ combining these frames and a photo of yourself that you take.

About

Juken

This app offers a fast and efficient way to review WaniKani vocabulary. It uses a minimalistic interface with swipe gestures for quick answer submission, inspired by popular flashcard and dating apps. A WaniKani account is required to use its features.

Highlights
  • Minimalistic design
  • Fast review process
  • Swipe gestures for answers
  • Tinder-like interface
  • WaniKani integration
Features
Read full description

Juken is a minimalistic review app for WaniKani optimized for speed. It eliminates the need for typing; just recall, reveal and swipe. The user experience was inspired by the popular flashcard app Anki in the sense that it allows you to reveal the answer instead of having to typing it out, and it features a Tinder-like swipe gestures to quickly submit your answers. Just login with your WaniKani Personal Access Token and start swiping. Note: This app requires a WaniKani account, which could be obtained at https://wanikani.com

Screenshots

Challenge with Erin4 screens
Juken4 screens

Verdict

The call

The clearest difference is review sentiment: Juken at 100% against Challenge with Erin's 63%. Juken also leads on update cadence (fortnightly vs every 5 months) and rating (5.0 vs 4.7). On price, ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Juken holds the better App Store score, 5.0 against 4.7. Both are backed by a comparable volume of ratings — 16 and 8 respectively. Written reviews point the same way: 63% of Challenge with Erin's written reviews are positive against 100% of Juken's.

UpkeepUpdate frequency

Challenge with Erin ships an update every 5 months, Juken fortnightly. The most recent releases landed on October 20, 2026 and October 24, 2026 respectively.

Scorecard4 real differences · 6 level
Challenge with Erin versus Juken: the parameters behind the verdict, then further details
ParameterChallenge with ErinJuken
PriceFreeFree
Rating4.7 (16 ratings)5.0 (8 ratings) — better
Positive reviews62.5% of reviews100.0% of reviews — better
Number of ratings16 — better8
Update frequencyEvery 5 monthsFortnightly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS12.010.0 — better
Further details — not scored
Size290 MB86 MB
Age rating4+4+
DeveloperThe Japan Foundation Japanese-Language Institute, KansaiOzBuilds, LLC

Customer experience

Challenge with Erin

All ratings16 ratings
Positive93.8%
Neutral0.0%
Negative6.3%
Written reviews24 reviews
Positive62.5%
Neutral12.5%
Negative25.0%

Juken

All ratings8 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews7 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Challenge with Erin

No in-app purchases

None

Juken

No in-app purchases

Questions

Is Challenge with Erin free?
Challenge with Erin is free to download, with no in-app purchases.
Is Juken free?
Juken is free to download, with no in-app purchases.
Which has better reviews, Challenge with Erin or Juken?
Juken is rated higher. Challenge with Erin averages 4.7 out of 5 from 16 ratings, while Juken averages 5.0 from 8 ratings.
Do Challenge with Erin or Juken have ads?
Neither Challenge with Erin nor Juken shows ads.
Which is updated more often, Challenge with Erin or Juken?
Challenge with Erin ships an update every 5 months, and Juken fortnightly. Most recently, Challenge with Erin was updated on October 20, 2026 and Juken on October 24, 2026.

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