Daily Jigsaw Sudoku (SudokuWiki)

SudokuWiki.org is a well-known reference for sudoku solving techniques, built by Andrew Stuart around his online solvers. Besides its strategy articles it runs a set of daily puzzles, and the Daily Jigsaw Sudoku is one of them. Each puzzle carries a running number, past 6,400 by October 2026, and the same puzzle is shown to everyone on a given day. The new grid goes up at about 03:00 UTC, so after midnight in the UK the previous day's puzzle is still the one on the page for a few hours.

A jigsaw sudoku, also called irregular sudoku, keeps the familiar rules: every row and column must contain the digits 1 to 9 once. The difference is that the nine 3x3 boxes are replaced by nine irregular shapes, shown in different colours, and each shape must also hold 1 to 9 once. This changes which deductions work and makes some familiar box tricks unavailable.

Each day's heading gives the number and the date (#6462 on 21 October 2026), and a star rating shows the difficulty. You click a cell and type a digit or press it on the number pad, switch on Notes to pencil in candidates, and a timer runs above the grid and keeps going across refreshes. Settings sit behind a cog icon, and a print version is linked above the puzzle. The free daily is one grade; All-Access supporters can play all four grades. The site's jigsaw solver can help if you want to learn the logic behind a step.

The page needs no account and works at phone size, where the grid fills the width of the screen. Ads sit in the side column, away from the grid. It suits sudoku players who want a regular variant and who like to learn the reasoning behind each step.