A Sudoku puzzle is a grid of numbers and a chain of reasoning. Neither one needs to be seen, and the app is built so that neither one has to be.
Everything below describes what the app does today, not what it intends to. If something here stops being true, this page changes.
Last reviewed 9 September 2026, against version 1.0.
The whole game can be played with the screen off. Every cell announces its position and its contents, so you always know where you are:
"Row 4, column 7, empty, candidates 2, 5 and 8."
"Row 1, column 3, given 9."
"Row 6, column 6, your 4, conflicts with row 6."
Each cell carries custom actions for Enter Digit, Toggle Note, Erase and Hear Candidates, so you never have to hunt for a control elsewhere on the screen. A custom rotor jumps between the cells that matter: empty cells, conflicts, every copy of the digit you are working on, the evidence behind the current hint, and the hint's target cell.
This matters more here than in most puzzle apps, because the hint is the app's main feature. Every hint carries its own spoken sentence, written to stand alone rather than to narrate the highlighting. "The only place 7 can go in box 3 is row 3, column 9" tells you the same thing the coloured cells tell a sighted player. The explanation, not the picture, is the thing being delivered.
The app uses Dynamic Type throughout and supports the accessibility text sizes. The board keeps its geometry so digits stay legible, control rows wrap rather than clip, and the hint panel grows with the text instead of cutting it off.
Every colour in the app is defined twice, once for light and once for dark, rather than being inverted automatically. The app follows your system appearance, and you can also force light or dark under Profile › Appearance.
With Reduce Motion on, hint transitions crossfade instead of sliding, and the celebration when you complete a row, column or box flashes its colour without scaling or lifting the cells. Nothing that carries meaning is conveyed by movement alone.
The board can be driven from a hardware keyboard: every cell is a real button, so it takes focus and works with Full Keyboard Access and Voice Control.
Nothing on the board is said with colour alone. Turn on Differentiate Without Color in iOS Settings and every state the board draws picks up a shape as well as a tint:
Two marks never wait on the setting, because they are the ones nobody should miss: a wrong digit always carries a dot in its corner, and a candidate a hint has eliminated is always struck through. The board has been checked in greyscale with the colour removed entirely.
Every piece of text in the app meets a contrast ratio of at least 4.5:1 against whatever it is drawn on — in light appearance and dark, in the interface and on the board itself, including pencil marks and the digits sitting on highlighted cells. This is not a judgement by eye. The app has a test that resolves each colour as it ships and measures it against every surface it can land on, so a shade nudged for looks cannot quietly drop a label below legibility.
If something in this app is hard or impossible to use, that is a bug and we want to hear about it. Email sudoku@bonendo.com and say what you were trying to do, what assistive technology you were using, and what happened instead. You will get a reply from a person.