Shichi Sudoku Online Help
Shichi Sudoku follows the same rules as Sudoku in that every row, column and block of each of the seven grids must contain the numbers 1 - 9.
Where the grids overlap, the rows and columns do not go beyond their usual length but the interlocking blocks give you more clues. Don't try to solve each of the five grids in turn, you must look at the puzzle as a whole to be able to solve it.
How To Play
- Move your cursor over the "New Puzzle" menu item and select a skill level from the dropdown menu.
- Fill in blanks with the Pen (select a cell, then click on the number you want to enter, or enter the number via the keyboard).
- If you're not 100% sure of a number, you can make a note of it in the cell using the Pencil. To do this, click the "Pencil" icon to be placed in "Pencil mode".
- You may enter as many pencil marks as you like in each cell.
- To change back to "Pen" mode, click the "Pen" icon. You can also switch between pen and pencil modes quickly by pressing the "P" key. (See tips below.)
If you prefer to use the keyboard rather than the mouse, you may:
- Use the arrow keys to navigate around the grid.
- Use the number keys to enter a number in the highlighted cell.
- Press the space or Delete key to remove any numbers from the highlighted cell.
- Press the "P" key to toggle between Pen and Pencil.
- Press the "U" key to undo last input.
- Hold Shift key down to enter in pencil (when in Pen mode).
- Click the Undo icon (yellow arrow) to undo last input. You can undo all the way back to the beginning.
- Holding the Shift key when clicking on a number in the input panel will pencil that number in. You may find this more convenient than toggling between the Pen and Pencil icons.
- To remove just one pencilled number in a cell, enter that number again.
- To remove all pencil numbers in a cell, either click the eraser button or simply "pen" the final choice in.
- To remove all pencil marks from all cells, use the menu option under "Edit".
- There is an alternate mode of number input via the mouse called "Active Number Mode" (see below).
Active Number Mode
If you select this mode (via Edit->Preferences menu option), then the number you click from the Number Pad on the right becomes the "active number". The mouse cursor will change to this number and clicking on any cell will enter it in that cell. This is the reverse of the "cell select" mode, where you highlight a cell and then select the number to input. Those that prefer to solve by focusing on one specific number at a time will find this mode much more convenient.
To change the active number, select a new one from the Number Pad or scroll the mouse wheel down/up to increase/decrease the number.
In the Active Number mode, all pencil functionality remains the same as does the ability to use the keyboard.
Description Of Menu Options
New Puzzle Menu
Here you can generate a puzzle at the required level of difficulty. All these puzzles are solvable by pure logic.
Note: Initially, there is only one new puzzle per level per day but you can play more from archives.
This will give you a list of puzzles at each level for the last two weeks.
This will undo the last move. You can undo all the way back to the beginning of the puzzle (unless you have loaded a puzzle which was partially completed).
This is the same as clicking the Undo icon (yellow arrow).
This will clear all possibles displayed in the grids.
Clear All Input
This will clear all input (pen and pencil marks) displayed in the grids.
Here you may set whether you want to display the timer, whether you wish automatic display of errors, whether you want sound effects or not or whether you want to enable "Active Number" mode. Auto error display means that as you enter a number in a cell, it will display in red if incorrect.
Preferences are remembered and will reload from what was last set on that computer.
Main options to aid in solving puzzles.
Checks to see if you have solved the puzzle correctly. Any errors made will be shown in red.
Suggests which cell may be the next easiest to solve. It will not fill in the value - for that you need to select the "Solve One Cell" option.
This will suggest you look where a particular number is located in a block, row or column and will highlight that area of the grid. This helps you more than the "Hint" option and is the easiest aid you can ask for, save getting the actual answer.
Solve One Cell
This option will fill in one of the cells and displays the reason why that number is the answer to the cell. If advanced strategies are required (hard and tough puzzles), it will walkthrough the steps to solve
the cell. Sometimes there may be additional steps shown which are not necessary for the solving of that cell but they offer a useful practice tool.
This option will show you the possible numbers for each unsolved cell using the most basic logic technique. It does this by looking at what numbers are already present in the same block, row and column.
This option still uses basic logic in determining possible numbers for each unsolved cell but it goes further by looking at each possible number in each cell and sees if this number can be placed anywhere else on the same row/column/block. If not, the possibles for that cell are reduced to just this number (ie it is the solution for that cell). This strategy is referred to as "OnePlace".
This option goes further by using more advanced solving strategies such as "Naked Pairs" and "Box-line Pointing" in determining possible numbers for each unsolved cell. These strategies are required to solve "Hard" puzzles.
For an explanation of these strategies, please consult the online tutorials.
This option goes one step further using more complex strategies such as "Hidden Pairs".
Solve the puzzle and shows the completed solution.
Loads the last saved puzzle on this computer.
Saves the current state of the puzzle to temporary user data on this computer. This is useful if you wish to come back another time to continue solving it, or if you are guessing which may necessitate you to backtrack later on.