Daily Anti Knight King Sudoku
The extra rule
No digit may repeat a king's move or a knight's move away.
Two restrictions stacked. A digit blocks the eight squares touching it and the eight squares a knight could jump to.
That is sixteen extra cells watching every digit, which is why these grids need fewer givens than a plain sudoku and why the deductions travel so far across the board.
Controls
Click a cell and type a digit, or use the pad. Space toggles pencil marks. Arrow keys move. Progress saves in this browser as you go, so you can come back to the same puzzle later today.
Solvable Without Guessing
Every puzzle here was generated and then handed to a solver that is only allowed techniques a person can use. If it could not finish the grid without a guess, the puzzle was thrown away rather than published. That also makes the answer unique, because every digit it placed was forced.
More to Play
There is also a kropki sudoku, a xv sudoku, a greater than sudoku, a nonogram with hand drawn pictures, and 2048. All of them are on the games page, and the solvers for real objects are on the puzzle tools page.