# 3sec Diary vs 観察日記

The clearest difference is in-app purchases: 観察日記 at none against 3sec Diary's 1. 観察日記 also leads on ads (none vs shown) and update cadence (weekly vs every 26 months). On price and device support there is nothing between them.

Both are free to download. 3sec Diary sells 1 one-off in-app purchase. 観察日記 asks for nothing beyond the download.

3sec Diary ships an update every 26 months, 観察日記 weekly. The most recent releases landed on November 1, 2026 and October 26, 2026 respectively.

## The numbers

| Metric | 3sec Diary | 観察日記 |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 60.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 26 months | **Weekly** |
| Monetization | Free with in-app purchases | — |
| Size | 12 MB | 53 MB |
| Requires iOS | 12.0 | **9.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [KENJI KANEMOTO](https://appshunter.io/developer/402720982) | [Yutaka Tajika](https://appshunter.io/developer/1063102537) |

## What reviewers say

### 3sec Diary

[App page](https://appshunter.io/ios/app/3sec-diary/id985967203)

Quickly log daily activities and feelings in just three seconds. Your entries are securely stored in your iPhone Calendar, ensuring data safety and easy access. This tool helps you preserve memories and makes research and sharing effortless.

**Highlights:** 3-second daily logging, Calendar integration, Secure data storage, Easy research and sharing, Memory preservation

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Eliminate Ads | $0.99 | one-time |


### 観察日記

[App page](https://appshunter.io/ios/app/id1063102538)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is 3sec Diary free?

3sec Diary is free to download, with in-app purchases available.

### Is 観察日記 free?

観察日記 is free to download, with no in-app purchases.

### Do 3sec Diary or 観察日記 have ads?

3sec Diary shows ads; 観察日記 does not.

### Which is updated more often, 3sec Diary or 観察日記?

3sec Diary ships an update every 26 months, and 観察日記 weekly. Most recently, 3sec Diary was updated on November 1, 2026 and 観察日記 on October 26, 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.*