# Fill One Line vs Kurotto Extreme

The clearest difference is update cadence: Fill One Line at every 9 months against Kurotto Extreme's every 22 months. Fill One Line also leads on iOS requirement (10.0 vs 13.0). On price, ads, 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.

Fill One Line ships an update every 9 months, Kurotto Extreme every 22 months. The most recent releases landed on October 20, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Fill One Line | Kurotto Extreme |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/kurotto-extreme/id1499171663/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | **Every 9 months** | Every 22 months |
| Monetization | — | Ad-supported |
| Size | 63 MB | 22 MB |
| Requires iOS | **10.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [HECTOR GAUCHIA SAFONT](https://appshunter.io/developer/869245759) | [Christophe Baranger](https://appshunter.io/developer/982794089) |

## What reviewers say

### Fill One Line

[App page](https://appshunter.io/ios/app/fill-one-line-logic-puzzles/id1217415915)

**In-app purchases:** none


### Kurotto Extreme

[App page](https://appshunter.io/ios/app/kurotto-extreme/id1499171663)

A logic puzzle game originating from Japan with simple rules for hours of engaging challenges. Fill empty cells based on numbered circles indicating continuous black cells, with no time limits and autosave functionality.

**Highlights:** 350+ challenges across 7 difficulty levels, 7 new daily challenges, Autosave progress, No time limits, 2 global leaderboards, Full tutorial

**In-app purchases:** none


## Frequently asked questions

### Is Fill One Line free?

Fill One Line is free to download, with no in-app purchases.

### Is Kurotto Extreme free?

Kurotto Extreme is free to download, with no in-app purchases.

### Do Fill One Line or Kurotto Extreme have ads?

Both Fill One Line and Kurotto Extreme show ads.

### Which is updated more often, Fill One Line or Kurotto Extreme?

Fill One Line ships an update every 9 months, and Kurotto Extreme every 22 months. Most recently, Fill One Line was updated on October 20, 2026 and Kurotto Extreme on October 5, 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.*