Rulehunt
Sudoku with a hidden rule
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Launch week. Every board hides one extra rule: read the refusals, test a hypothesis, name the rule. A free hunt every day, no ads, no account. One purchase unlocks it.
Sudoku, but we won’t tell you the rule.
Every board in Rulehunt is an ordinary sudoku with one extra rule hidden inside it. The board refuses any digit that breaks that rule — and every refusal is caused by a digit you can already see. Your job is not just to fill the grid. It is to work out what the rule is.
HOW A HUNT GOES
• Solve as far as ordinary logic takes you.
• Try a digit. If the hidden rule forbids it, the board refuses — a red mark, no penalty.
• Point at the visible digit you think explains the refusal. The board confirms or denies.
• Test a hypothesis: light up the cells a knight’s move away, the neighbours, the diagonals, and watch which explanation fits.
• Name the rule in your own words — “cells a knight’s move apart cannot hold the same digit” — and record it in your bestiary.
WHAT IS IN THE BOX
• Five short lessons that teach the hunt in a few minutes.
• A quick daily investigation (15–20 cells) and a full daily board, the same for everyone, with a streak.
• A mystery casebook of twelve authored cases. The first three are free.
• Expeditions: three sets of twelve boards, each introducing new rules, ending in an exam.
• A bestiary of twelve rules to discover and master.
• Custom hunts: pick a difficulty, let the board surprise you.
ONE PURCHASE, NO SUBSCRIPTION
The lessons, the dailies, the first expedition, three cases and three custom hunts a day are free. The Full Game is a single purchase: nine more cases including two paired-rule finales, expeditions two and three, and unlimited custom hunts. No ads, no account, no tracking.
Refusals never cost you anything. Digit trials are how you learn. Rulehunt is about the moment the board says no and you realise why.
Languages: English, German, Japanese, Korean.
Ratings & Reviews
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The developer, Suleyman Ozdemirci, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- User Content
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Suleyman Ozdemirci
- Size
- 20.8 MB
- Category
- Puzzle
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Full Game $2.99
- Copyright
- © 2026 Süleyman Özdemirci