Objective / Rules - Divide the grid into groups. - Every square must contain a number, and the number indicates how many squares are in that group. - Squares in groups are only linked horizontally and vertically. - You may initially be given two or more numbers in the same group.
Keyboard Usage Note: only when supported by your computer/device/browser/etc. Pressing a number key will 'pick up' that number and it will become selected. When '0' is selected it will act like the right-click.
Mouse Usage Note: only when supported by your computer/device/browser/etc. Left-click on number square = 'pick up' and select number. Left-click on blank square = fill in square with selected number (the grid on the left shows which number is selected). Right-click = Clear a number (you can't clear initially given numbers). Click the numbers on the left to 'pick up' number, selecting X allows you to clear numbers.
Checking If you click 'Check' the system will check for incorrect squares. If 'Show mistakes when checking' is checked they will be marked in red.
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.