# Mars Book vs ClockCompass コンパス時計

The clearest difference is ads: Mars Book at none against ClockCompass コンパス時計's shown. Mars Book also leads on iOS requirement (9.0 vs 12.1). ClockCompass コンパス時計's advantage is update cadence (every 10 days vs every 13 months). On price, in-app purchases and device support there is nothing between them.

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

Mars Book ships an update every 13 months, ClockCompass コンパス時計 every 10 days. The most recent releases landed on September 28, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | Mars Book | ClockCompass コンパス時計 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 13 months | **Every 10 days** |
| Size | 14 MB | 15 MB |
| Requires iOS | **9.0** | 12.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) | [takayuki atsumi](https://appshunter.io/developer/1495474977) |

## What reviewers say

### Mars Book

[App page](https://appshunter.io/ios/app/mars-book/id1342509724)

**In-app purchases:** none


### ClockCompass コンパス時計

[App page](https://appshunter.io/ios/app/clockcompass/id1500240108)

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

**In-app purchases:** none


## Frequently asked questions

### Is Mars Book free?

Mars Book is free to download, with no in-app purchases.

### Is ClockCompass コンパス時計 free?

ClockCompass コンパス時計 is free to download, with no in-app purchases.

### Do Mars Book or ClockCompass コンパス時計 have ads?

ClockCompass コンパス時計 shows ads; Mars Book does not.

### Which is updated more often, Mars Book or ClockCompass コンパス時計?

Mars Book ships an update every 13 months, and ClockCompass コンパス時計 every 10 days. Most recently, Mars Book was updated on September 28, 2026 and ClockCompass コンパス時計 on October 11, 2026.

---

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