# Kurotto Extreme vs Index Sums

The clearest difference is ads: Index Sums at none against Kurotto Extreme's shown. Index Sums also leads on update cadence (every 3 weeks vs every 22 months) and monetization model (free vs ad-supported). Kurotto Extreme's advantage is iOS requirement (13.0 vs 17.6). On price, rating, review sentiment and in-app purchases there is nothing between them.

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

On the App Store both sit at effectively the same score — 5.0 for Kurotto Extreme against 5.0 for Index Sums. Both are backed by a comparable volume of ratings — 1 and 3 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Kurotto Extreme ships an update every 22 months, Index Sums every 3 weeks. The most recent releases landed on October 5, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | Kurotto Extreme | Index Sums |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/kurotto-extreme/id1499171663/reviews) | [5.0 (3 ratings)](https://appshunter.io/ios/app/index-sums/id6745894447/reviews) |
| Number of ratings | 1 | **3** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 22 months | **Every 3 weeks** |
| Monetization | Ad-supported | **Free** |
| Size | 22 MB | 25 MB |
| Requires iOS | **13.0** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Christophe Baranger](https://appshunter.io/developer/982794089) | [ZORIX LLC](https://appshunter.io/developer/1814371874) |

## What reviewers say

### 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


### Index Sums

[App page](https://appshunter.io/ios/app/index-sums/id6745894447)

Engage your mind with a Japanese number logic puzzle. Fill grids based on row and column sums, using pure logic to reveal hidden patterns. Offers multiple difficulty levels and daily challenges for continuous mental stimulation.

**Highlights:** Row and column sum logic puzzles, Multiple difficulty levels, Daily challenges, Progress tracking and statistics, Offline play, Customizable themes, Haptic feedback

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Kurotto Extreme free?

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

### Is Index Sums free?

Index Sums is free to download, with no in-app purchases.

### Which has better reviews, Kurotto Extreme or Index Sums?

Kurotto Extreme and Index Sums are both rated 5.0 out of 5 on the App Store, from 1 and 3 ratings respectively.

### Do Kurotto Extreme or Index Sums have ads?

Kurotto Extreme shows ads; Index Sums does not.

### Which is updated more often, Kurotto Extreme or Index Sums?

Kurotto Extreme ships an update every 22 months, and Index Sums every 3 weeks. Most recently, Kurotto Extreme was updated on October 5, 2026 and Index Sums on October 9, 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.*