Sudoku variant · rules and tips

King's Move Sudoku

No two identical digits may sit a chess king's move apart. A king steps one square in any direction, diagonals included, so none of the eight cells surrounding a digit may repeat it. A monarch who insists on personal space.

Get it onGoogle PlayPlay King's Move Sudoku on the web
Professor Cryptic, the owl who teaches in the app
Professor Cryptic explains the rule

The Professor's tips

How do you solve King's Move Sudoku?

01 / Warm up

Start on a 4 by 4 grid

  • The rule forbids a repeat in any touching cell, diagonals included. On a grid this small that is a severe restriction.
  • A corner cell touches three neighbours, an edge cell five, a central cell eight. Begin in the centre, where the rule is tightest.
  • The box rule already keeps a 2 by 2 box distinct. What the king adds is a prohibition across box boundaries, and along the diagonals in particular.
02 / Level up

Then try a 6 by 6 grid

  • Every cell has as many as eight neighbours that may not share its digit. Add the row, column and box rules and the candidates fall away quickly.
  • Picture a 3 by 3 exclusion zone around each digit you place, the cell itself excepted. Nothing in that zone may repeat it.
  • The rule tells you most at the boundaries between boxes, where it links cells diagonally across the join.
  • Whenever you place a digit, check all eight surrounding cells. The diagonal neighbours are the ones that escape notice.

The rule, drawn

What does King's Move Sudoku look like?

  1. King's Move Sudoku rule illustration, step 1 of 2
  2. King's Move Sudoku rule illustration, step 2 of 2

Start with a single square

Where can you play King's Move Sudoku?

King's Move Sudoku is one of the 17 variants in Cryptic, each with a lesson and unlimited puzzles.

Get it onGoogle PlayPlay on the web