Apps by Detlev Voss

A second app is on the way. Sudoku — a clean, distraction-free logic puzzle for iPhone and iPad — will be submitted to the App Store very soon.

What to expect at launch

The first version is built around one idea: a Sudoku you can sit down with and just play, without ads, without tracking, and without anything fighting for your attention.

• Pure logic — every puzzle has exactly one solution and can be solved by logic alone. You never need to guess.
• Five difficulty levels from Simple to Expert. Each level caps the hardest solving technique a puzzle will ever require, so the challenge grows gradually.
• Pencil notes for candidates, with a single-tap switch between pencil mode and final entry.
• Hint, Show & Check — a gentle nudge, a filled-in answer, or a sweep for wrong digits, whenever you want one.
• Built-in strategy guide covering the classic techniques from Naked Singles and Hidden Pairs up to X-Wing, XY-Wing, Coloring and Forcing Chains.
• Challenge Mode for when you want to put your skills to the test — all help is disabled, wrong entries are flagged immediately, and three mistakes end the game.
• Light and dark mode, with the 3×3 blocks clearly visible in either theme.
• iCloud sync for your preferences across your iPhones and iPads, kept in your private iCloud.

Look around in the meantime

The marketing page and the in-app help are already on this site, so you can get a feel for the app before it lands in the App Store:

• Sudoku overview — features and screenshots.
• Sudoku help — rules, controls, and the full strategy guide.

When Sudoku goes live, there will be a launch post here with the App Store link. If you’d like to be reminded, the RSS feed is the calmest way to hear about it.