Daily Anti King Sudoku
The extra rule
No digit may repeat a king's move away.
Treat every digit as a chess king. None of the eight squares around it, diagonals included, may hold the same digit.
Rows, columns and boxes already stop digits repeating sideways and up and down, so what this really adds is the diagonals. Two equal digits can never sit corner to corner again.
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.