# 瞬間英作文 vs Kusari

The clearest difference is in-app purchases: 瞬間英作文 at none against Kusari's 1. Kusari's advantage is iOS requirement (15.1 vs 26.2). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Kusari sells 1 in-app purchase, starting at $29.99 per month. 瞬間英作文 asks for nothing beyond the download.

瞬間英作文 ships an update fortnightly, Kusari every 10 days. The most recent releases landed on November 9, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | 瞬間英作文 | Kusari |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Fortnightly | **Every 10 days** |
| Monetization | — | Free with in-app purchases |
| Size | 75 MB | 123 MB |
| Requires iOS | 26.2 | **15.1** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [COBALT LEAF](https://appshunter.io/developer/1838292901) | [RYUTA ABE](https://appshunter.io/developer/1895880547) |

## What reviewers say

### 瞬間英作文

[App page](https://appshunter.io/ios/app/id6759487459)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Kusari

[App page](https://appshunter.io/ios/app/kusari/id6764690812)

This app uses behavioral economics to build a daily English learning habit. It employs a commitment device where users risk losing money if they miss their daily tasks, encouraging consistent practice through financial stakes rather than willpower. Daily activities include reading, shadowing, and AI conversation, taking 15-20 minutes.

**Highlights:** Commitment device with financial stakes, Daily reading, shadowing, and AI conversation, 15-20 minute daily tasks, Behavioral economics principles applied, Dynamic skill level adjustment (CEFR A1-C2), Tiered pricing based on daily achievement

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Kusari Monthly | $29.99 | per month |


## Frequently asked questions

### Is 瞬間英作文 free?

瞬間英作文 is free to download, with no in-app purchases.

### Is Kusari free?

Kusari is free to download, with in-app purchases available.

### Do 瞬間英作文 or Kusari have ads?

Neither 瞬間英作文 nor Kusari shows ads.

### Which is updated more often, 瞬間英作文 or Kusari?

瞬間英作文 ships an update fortnightly, and Kusari every 10 days. Most recently, 瞬間英作文 was updated on November 9, 2026 and Kusari on October 31, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*