Be sure to make a backup copy of the grid before using it for the first time.
Copying the puzzle digits
You can type in the puzzle grid digits before printing (the digits will appear in the Notes and Scratch Grids also). If desired, fill in the header (puzzle source, difficulty, etc.) and name and comment fields. Select where to type with a mouse or touch screen, then simply type with the keyboard. Print as many copies as will be needed because the filled-in form cannot be saved.
You can also print multiple copies of the blank form whenever you want and use them wherever you wish. When solving, we suggest copying the puzzle digits in pen while working in pencil so you can distinguish the “given” cells.
The labels A-I and 1-9 along the left and top of the main grid identify individual cells. These are usually written row first. For example, the grid’s top right cell is A9. The labels are useful for recording for backtracking and in discussing the puzzle.
This grid is for sequentially recording the cells you fill in. If you find a mistake, you can erase cells backward to the mistake, then continue. It also shows the last cell you did if you stop working and pick up the puzzle later.
In each cell the digits 1-9 are printed lightly around the edges. They are used in limiting possible entries for each cell. Use or ignore these as you wish. People typically cross out digits that cannot go in a cell or circle the digits that can.
When you have filled in all nine of any digit, cross it out in the row of “Completed” digits. When scanning later, you can ignore all the Completed digits. Also, you can record that a row or column is complete by crossing out the respective row or column label.
The scratch mini-grids are available for testing solutions. In harder puzzles you simply need to work out a potential path to see if it leads to a solution or contradiction.
You can use the notes area below the main grid to help recognize patterns in the “possible” digits if it’s hard to analyze these in the full grid. Copy the “possible’s” to the corresponding cells in the notes area. Another use is an alternative way to backtrack – fill sequential numbers in notes cells corresponding to main-grid cells you solve.