Proven Sudoku
Features / Shaped boards
Four shaped sudoku boards, each adding one rule
Four boards that are ordinary sudoku plus exactly one extra rule, playable at every level.
The problem
Variant sudoku usually arrives as a pile of unfamiliar names with no way in. You cannot tell which are a small step from the game you know and which will need an evening of reading, so most people never try any of them.
How it works
Each shape adds one rule and nothing else. Diagonal means both long diagonals hold 1 to 9 as well. Windoku adds four shaded windows that each hold 1 to 9. Anti-knight means no digit repeats a knight's move away. Anti-king means no digit repeats a king's move away, corners included. Where the rule can be shown on the board it is shaded, and where it cannot be, the board says so rather than leaving you to guess. Every shape is playable at every level, one is featured each week, and they change on Monday rather than at midnight.
Image to add: The four shaped boards, showing which shade their rule and which cannot. The repository holds no product screenshots yet, only the 68 technique diagrams, so nothing is shown here rather than something invented.
What you would use it for
Try a variant without a reading list
One added rule is small enough to hold in your head on the first board. You already know the rest of the game.
Keep the classic game as the default
The daily Easy, Medium and Hard are always classic sudoku. The shapes sit beside them and never replace them.
Play the week out
A shaped board stays put until Monday, so there is time to come back to one rather than losing it at midnight.
Learn how to use it
How to play walks through the controls step by step.
Related
- The daily puzzleThree boards a day, the same three for every player in the world, new at midnight UTC.
- Difficulty you can trustEach level is defined by the hardest technique a board really needs, and every board is checked before anyone sees it.
- Pencil marks and hintsEverything you need to work a board, and a hint that refuses to solve it for you.