My turn features a sudoku variant I'm not hugely comfortable either constructing, or solving, so it'll be interesting to see how the others get on. In case "Anti-Knight" needs further explanation, all this means is that two cells a Knight's move away from each other cannot contain the same digit. Equivalently, the same digit cannot be in opposite corners of any 2x3 or 3x2 subgrouping of cells in the grid.
I'll tentatively say medium for this puzzle. Enjoy!
#228 Anti-Knight Sudoku – rated easyAll puzzles © Tom Collyer 2009-13.