X-Sudoku (PuzzleMadness)

X-Sudoku is a classic 9x9 sudoku with one extra rule: the two long diagonals, corner to corner, must each hold 1 to 9 once, just like a row or column. The diagonals give extra information, so a square on a diagonal often has fewer candidates than it would in a plain grid.

The daily page opens today's puzzle on its own, and its title carries the date (on 3 October 2026 it read "Daily Medium X-Sudoku Puzzle for Saturday 3rd October 2026 (Medium)"). There are five dated grids a day: one each at Easy, Medium and Hard, one at Tough, and a fifth on the Mixed page. The Mixed grid is a puzzle of its own, and its level changes from day to day (it was an Easy grid on 28 October 2026). Past days stay in the archive, so a missed puzzle can be played later, and there is a print version and an image download of the grid. PuzzleMadness does not publish solutions: the site tells you when you have finished a grid correctly or made a mistake. Each completed puzzle adds to your total on the X-Sudoku monthly and all-time leaderboards, where only your best score on any one puzzle counts.

Remember the centre square sits on both diagonals and in the middle row, column and box at once, so it is one of the most constrained squares in the grid. Otherwise solve as usual and check the diagonals whenever a square on them gets down to two candidates.

PuzzleMadness is a British puzzle site with dozens of daily puzzle types in the browser, from many sudoku variants to logic grids such as Nurikabe, Hashi and Slitherlink. It is free to play and carries ads. A free account keeps track of the puzzles you have finished and puts your name on the leaderboards, and the badges next to usernames mark how many puzzles a player has completed.