iPhone · sudoku

A sudoku that lets you think.

Istind is a quiet sudoku for iPhone. No ads, no accounts, no tracking, no streak nagging you from a notification. Every puzzle is created on your device and has exactly one solution.

It is built around one idea that most sudoku apps get backwards: the app should not do the thinking for you. A digit that breaks a rule is marked, because that is a rule, not a judgement. A wrong digit that still fits is left alone — finding it is part of the puzzle, exactly as it is on paper.

When you do get stuck, the coach explains the next step in four stages instead of filling in the answer: where to look, what the evidence is, why it follows, and only then the move itself. You can stop at any stage and take it from there yourself.

Privacy No accounts, no analytics, no network. Nothing leaves your phone — read exactly what that means. Support How the coach, the daily puzzle and the technique entry work — and how to reach a human.

NorwayWho made this

Istind is built by Øivind Kongsjorden at Kongsjorden Studio — websites, apps and digital work, made for people who have to use them every day. Have something that needs building? The studio is the place to ask.