# KSM予約 vs 世界史年号問題

The clearest difference is in-app purchases: KSM予約 at none against 世界史年号問題's 1. KSM予約 also leads on ads (none vs shown) and iOS requirement (13.0 vs 16.6). 世界史年号問題's advantage is update cadence (every 3 weeks vs every 3 months). On price and device support there is nothing between them.

Both are free to download. 世界史年号問題 sells 1 one-off in-app purchase. KSM予約 asks for nothing beyond the download.

KSM予約 ships an update every 3 months, 世界史年号問題 every 3 weeks. The most recent releases landed on October 20, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | KSM予約 | 世界史年号問題 |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 82.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Size | 30 MB | 15 MB |
| Requires iOS | **13.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [K S MUSIC, Y.K.](https://appshunter.io/developer/1454205339) | [Akira Fujisawa](https://appshunter.io/developer/1533514621) |

## What reviewers say

### KSM予約

[App page](https://appshunter.io/ios/app/ksm/id1517172323)

**Features:** macOS Compatibility

**In-app purchases:** none


### 世界史年号問題

[App page](https://appshunter.io/ios/app/id1591797286)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 広告非表示 | $4.99 | one-time |


## Frequently asked questions

### Is KSM予約 free?

KSM予約 is free to download, with no in-app purchases.

### Is 世界史年号問題 free?

世界史年号問題 is free to download, with in-app purchases available.

### Do KSM予約 or 世界史年号問題 have ads?

世界史年号問題 shows ads; KSM予約 does not.

### Which is updated more often, KSM予約 or 世界史年号問題?

KSM予約 ships an update every 3 months, and 世界史年号問題 every 3 weeks. Most recently, KSM予約 was updated on October 20, 2026 and 世界史年号問題 on October 25, 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.*