# 空の青さを知る vs Crimsooon Sun

The clearest difference is price: 空の青さを知る at Free against Crimsooon Sun's $1.99. Crimsooon Sun's advantage is update cadence (every 4 days vs monthly) and iOS requirement (13.0 vs 15.5). On ads, in-app purchases and device support there is nothing between them.

空の青さを知る is free to download; Crimsooon Sun costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

空の青さを知る ships an update monthly, Crimsooon Sun every 4 days. The most recent releases landed on October 3, 2026 and October 2, 2026 respectively.

## The numbers

| Metric | 空の青さを知る | Crimsooon Sun |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Monthly | **Every 4 days** |
| Monetization | — | Paid |
| Size | 86 MB | 248 MB |
| Requires iOS | 15.5 | **13.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 9+ | 12+ |
| Developer | [chiaki matsuda](https://appshunter.io/developer/1602664460) | [Kyohei Yamada](https://appshunter.io/developer/1583465790) |

## What reviewers say

### 空の青さを知る

[App page](https://appshunter.io/ios/app/id1602664458)

**Features:** macOS Compatibility

**In-app purchases:** none


### Crimsooon Sun

[App page](https://appshunter.io/ios/app/crimsooon-sun/id6739424746)

Experience a unique mystery novel adventure where your intuition guides you through a captivating narrative. Deduce the truth by pulling the trigger on your interests, with no branching paths or game overs. Focus on unraveling the mystery as if reading a detective novel.

**Highlights:** Deductive reasoning gameplay, Linear narrative structure, Intuitive clue gathering, No multiple endings, Detective novel immersion, Single-shot deduction system

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

**In-app purchases:** none


## Frequently asked questions

### Is 空の青さを知る free?

空の青さを知る is free to download, with no in-app purchases.

### Is Crimsooon Sun free?

Crimsooon Sun costs $1.99, with no in-app purchases.

### Do 空の青さを知る or Crimsooon Sun have ads?

Neither 空の青さを知る nor Crimsooon Sun shows ads.

### Which is updated more often, 空の青さを知る or Crimsooon Sun?

空の青さを知る ships an update monthly, and Crimsooon Sun every 4 days. Most recently, 空の青さを知る was updated on October 3, 2026 and Crimsooon Sun on October 2, 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.*