Instructions

• Hit the Clear button and enter the Sudoku 'givens' manually. You can do this by clicking on a cell, or use the keyboard arrow keys, then type the digit from '1' to '9'. The Delete key or the '0' key will clear a cell. You can also enter a digit or clear it by clicking in the row of digits above the board.
• When you are finished hit the Load button. The givens will now appear in blue.
• Hitting the Reset button will now undo all changes and take you back to the original givens.
• The allowed digits are shown as a small light gray digit in the background of each cell. You can turn this off by unticking the 'Show allowed' option.
• If an allowed digit is the only possible digit (these are called singles) then it is highlighted in red. You can turn this off by unticking the 'Show singles' option.
• Hitting the Accept button will convert singles to actual entered digits.
• The Hint button will fill in the current selected cell with the correct digit.
• Clicking in a cell with a digit entered will highlight the same digit anywhere alse in red.
• Solve of course will solve the entire puzzle.
• Undo will undo the last user action such as entering a digit or htting the Accept button.