Accessible Sudoku: screen readers, large print and high contrast

Sudoku is a puzzle of logic, not eyesight. With the right settings it works with a screen reader, at large sizes, in high contrast and one-handed. This page covers what helps, and how Ninebloom does each part.

Playing with a screen reader

A Sudoku board is a grid of 81 small cells, which is hard to explore by touch unless every cell says where it is and what it holds. In Ninebloom, with TalkBack on, each cell reads its position and contents, for example "Row 4, column 3, empty, notes 2 5 7", and says when a digit is a given clue, wrong (if checking is on) or coloured. In Killer and Jigsaw it adds the cage sum or region.

Moves are announced as you make them: the digit and cell you placed, when a row, column or box is complete, and when the puzzle is solved. Switching notes mode is announced too.

Hints are spoken in full. A hint names the technique and explains it in words, like "In box 4, the digit 6 has only one place left: R5C2. Every other cell in it is blocked.", so you can learn to solve by ear rather than getting a digit you can't see.

Large print and zoom

• Text size: Standard, Large or Extra large for the board and number pad.
• Zoom: pinch the board, or use the + and − buttons if pinching is awkward.
• Highlight matching digits: select a digit and every copy of it lights up, so you don't have to scan for it.

High contrast and colour vision

The High contrast theme is black on white, with one strong blue for your own digits, a yellow selection and errors shown in vermilion plus an underline, so nothing relies on colour alone. Its colours come from the Okabe-Ito palette, chosen to stay distinguishable with every common colour-vision deficiency. You can also turn off the per-digit colours on the pad and board.

Hands and motion

• Left-handed layout puts the controls on the left in side-by-side layouts and mirrors the tools.
• Digit first: pick a digit once, then tap every cell it goes in, instead of switching back and forth.
• Reduce motion follows your phone's setting, or can be forced on.
• No mistake limit unless you turn one on, and no timer pressure: the timer can be hidden.

Cost

All of this is free. Large print, high contrast, screen-reader play and the left-handed layout are on Ninebloom's list of things that stay free for everyone, along with classic Sudoku at all six levels and unlimited hints.