Objective / Rules - Complete the grid such that every row, every column, and every 3 x 3 block contains the digits from 1 to 9. - Every cage has a little clue in the corner, and digits in each cage must add to the clue. - A digit cannot appear more than once in a cage. - I have provided a page that shows possible combinations.
Help Read the help page on Killer Sudoku for a more detailed explanation and a walkthrough.
Pencil Marks What is a pencil mark? Pencil marks can help you keep track of your own thinking, simply enter more than one digit/letter into each square, just like you might do if you were using pen and paper. The size of the digits/letters is smaller when there is more than one digit/letter in a square. A square might contain more pencil mark digits/letters than can be shown.
Keyboard Usage[only when your cursor is in the grid] Note: only when supported by your computer/device/browser/etc. A = auto-pencil marks (or click the check box). P = show a pinned square. CTRL + arrows = move around the grid. SHIFT + digit = highlight all squares with that digit [SHIFT+0 to clear].
Checking If you click 'Check' the system will tell you to use the 'Show Errors' option to check your solution.
Uniqueness Each puzzle has exactly one solution, which can be found using logic alone and no guesses are ever required. If you think you've found another solution, then please double check the rules.