# Endoku — Concentric number logic puzzle

> Concentric number logic puzzle (iPhone/iPad app by seiji honda.)

- Source: https://appshunter.io/ios/app/endoku/id6778001734 (this page in markdown: same URL + `.md`)
- Developer: [seiji honda](https://appshunter.io/developer/1896430544)
- Category: Games, Casual, Puzzle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 16.0 · 3 MB
- Languages: Japanese
- Released: 2026-06-09
- Data updated: 2026-08-15
- User reviews in markdown: https://appshunter.io/ios/app/endoku/id6778001734/reviews.md

## What is Endoku?

No annoying ads, no data collection.

Endoku is a single-player logic puzzle played on concentric rings, where you place numbers so each radial line adds up. Just two rules:
• Each ring uses its set of numbers exactly once.
• The cells along each radial line must add up to the same target.

From these two simple rules, pure logic — never guessing — leads you to the one solution. Every puzzle is generated to be solvable by logic alone. Fresh for anyone who bounced off Sudoku, and meaty enough for anyone a little bored of it.

Features:
• Four board modes: Intro (2 rings) / Basic (3) / Advanced (4) / Expert (5)
• Three difficulties (Easy / Medium / Hard)
• Pencil marks (candidate notes) to work through the tougher boards
• A fresh Daily puzzle with a calendar and streaks
• A built-in strategy guide
• Calm music and satisfying sound effects (each toggleable)
• Gentle haptics
• A calm, easy-on-the-eyes board
• Japanese / English, portrait & landscape

Intro and Basic (Easy/Medium) are free.
A single one-time purchase unlocks all modes and difficulties, daily puzzles, the strategy guide, and music & sound.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Unlock Everything | $0.49 | one-time |



## Version history (last 5 releases)

### 1.3.0 — 2026-07-18

• Improved hint accuracy — hints now always find a next move
• Fixed issues around the daily puzzle
• Fixed purchase and restore reliability issues
• Minor stability improvements

### 1.2.0 — 2026-06-19

• Smarter hints: the hint now shows the next deducible cell and explains the technique behind it.
• Added Undo / Redo.
• Added Stats (solved count, average time, and best streak).
• Minor bug fixes and improvements.

### 1.1.0 — 2026-06-13

• Added pencil marks (candidate notes) to help with the tougher boards.
• Added a confirmation dialog before Clear to prevent accidental wipes.
• Faster app launch.
• Various minor improvements.

### 1.0.1 — 2026-06-11

- Stability improvements and minor refinements.
- Refreshed App Store screenshots.

### 1.0 — 2026-06-09

No release notes.

## More apps by seiji honda

- [Lock2Cam](https://appshunter.io/ios/app/lock2cam/id6767222283)
- [Tilt Hit](https://appshunter.io/ios/app/tilt-hit/id6767581735)
- [Hertz Sense](https://appshunter.io/ios/app/hertz-sense/id6767974523)
- [Causal Loop Diagram](https://appshunter.io/ios/app/causal-loop-diagram/id6769942289)
- [Wash&Shine](https://appshunter.io/ios/app/wash-and-shine/id6769987213)
- [Tippy Brim](https://appshunter.io/ios/app/tippy-brim/id6769992872)

All apps by seiji honda: https://appshunter.io/developer/1896430544

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-15.*