• Digit First mode vs Cell First Mode

    Select
    Digit
    First
    Digit First mode: Pick a digit from the numeric key panel first and then pick a cell where you would like to operate (add/remove) that certain digit.
    Select
    Cell
    First
    Cell First mode: Pick a cell in the Sudoku grid first and then pick a digit that you would like to operate in that certain cell.

    The default is the Digit First mode. Users can switch between these two modes by clicking the icon.

    Note to Computer Users: You can always use the mouse to input/delete a digit or to select a certain cell in the grid. However if you want to use the computer keyboard instead, such keyboard operations can be performed in "Cell First" mode and cannot be done in "Digit First" mode.

  • Regular Entry mode vs Pencil Mark mode

    Our Sudoku grid allows digits with two font sizes. The larger font is a regular entry, which is regarded as the digit that has been determined to be placed in the cell. The small font pencil mark is regarded as a candidate digit in the cell, which has not yet been determined.

    Regular Entry mode: In Regular Entry mode, when a certain digit N is picked to operate in a certain cell, it will follow the rules below:
    1. If the cell is empty, the digit N will be placed in the cell as a regular entry.
    2. If the cell is filled with pencil marks (candidate digits), all candidate digits will be removed and replaced by the regular digit N.
    3. If the REGULAR ENTRY digit N has been placed in that cell, it will be removed from that cell and that cell will become empty. It is equivalent to removing the regular entry digit N from the cell.
    4. If a REGULAR ENTRY digit other than the digit N has been placed in that cell, no operation will be performed. If you want to place the digit N in that cell, you need to remove the existing regular entry digit first.
    Pencil Mark mode: In Pencil Mark mode, when a certain digit N is picked to operate in a certain cell, it will follow the rules below:
    1. If the cell is empty, the digit N will be added to the cell as a candidate in a small font (pencil mark).
    2. If the cell is filled with pencil marks (candidate digits) and the digit N IS NOT one of the those, the candidate digit N will be added to the cell as another candidate.
    3. If the cell is filled with pencil marks (candidate digits) and the digit N IS one of the those, the candidate digit N will be removed from the cell.
    4. If ANY REGULAR ENTRY digit has been placed in that cell, no operation will be performed. No pencil mark entries can change any regular entries.
    The default is the Regular Entry mode. Users can switch between these two modes by clicking the pencil icon.
    How to remove a specific pencil mark, candidate digit "5" say, from a certain cell?
    1. Switch to "Pencil Mark" mode first.
    2. Computer KEYBOARD users must use Cell First mode. Other users, including computer users who use mouse only to operate (no keyboard operations), can use either Digit First mode or Cell First mode.
      • Digit First mode: Select the digit "5" from the key pad and then click on the cell that has the candidate digit "5" you want to remove.
      • Cell First mode: Click to select the cell that has the candidate digit "5" you want to remove and then click on the digit "5" from the key pad (computer keyboard users: press the digit "5" key on the keyboard).

  • Numeric Key Panel (or called Digit Panel)

    1

    3

    2

    5

    3

    4

    4

    5

    5

    2

    6

    3

    7

    5

    8

    3

    9

    4

    X

    The numeric key panel is composed of ten buttons which are digit buttons from 1 to 9 and a delete button "X". The user can pick a digit from this panel to add it to a cell or remove it from a cell. If the delete button "X" is applied to a cell, all entries in that cell will be deleted. The small font number in the lower right corner of each digit key represents how many times the corresponding digit still needs to be filled in the 9x9 grid.

  • Other Functional Buttons

    123456789
    All
    Fill in all possible candidates for all EMPTY cells. Possible candidates are those digits not found in the related area (the same row, the same column or the same 3x3 block) of that cell.

    0:00

    Timer: click to start/stop.
    Left: Undo button. / Right: Redo button.

    Two options:

    1. Check "mistakes": Check your regular entries against the solution of the puzzle and alert you all mistakes you have made.
    2. Check "violations": Check for obvious violations of Sudoku rules (more than one appearance of a certain digit in a row, a column or a 3x3 block). It will not show all violations but one at a time. Important Note: This feature does not check your entries against the solution of the puzzle. It just checks for obvious Sudoku rule violations. That means it will not alert you if you make a mistake that does not violate the Sudoku rules. If you get to the stage where the puzzle seems to have no solution, and this feature does not alert you to any Sudoku rule violations, it is certain that you made a mistake in a step and that mistake did not violate the Sudoku rules at the time.
    Restart the game - all entries will be erased.

  • More Tools

    Tools ▼
    The auxiliary tools below are under the label "Tools". Click on this label to show or hide these tools.
    The default state of this button is off. When this button is on, clicking a cell will highlight the related area (all cells in the same row, the same column or the same 3x3 block) of that cell.
    The default state of this button is off. When this button is on, the user can highlight the background color of a certain cell with one of the four colors. If the "white" color is used, it is equivalent to removing the existing background highlight color from the cell.
    X
    X
    X
    X
    Clicking this button will remove the background color from all highlighted cells in the entire Sudoku grid.
    49
    236
    Clicking this button will erase all pencil mark candidates in the entire Sudoku grid.
    3>>>3

    Clicking this button will convert all single candidate digits into regular entries in the entire Sudoku grid.

    Auto:

    The default of this "Auto" option for this function is off. If this option is turned on and the number of candidates in a cell is REDUCED to one, the remaining candidate in that cell will be automatically converted into a regular entry. Note that if a candidate is added to an empty cell, that candidate will not be automatically converted even though this cell has only one candidate. This action will be performed only when the number of candidates is REDUCED to one.

  • Step by Step Solution for the Puzzle

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    Save

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