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SuDoku (current version V4.20, October 2025)

The puzzle is displayed in an Excel spreadsheet, which works in most versions which support the Control Toolbox*

The puzzle can be cleared and a new one input manually and saved mid way for completion later.

Inputting a table and all operations are explained in the Rules tab

There are optional different levels of highlighting possible, with a user choice of colour scheme.

1) Original or sure entered numbers can be highlighted to simplify back tracking in case of an error.

2) Any single number at a time can be highlighted to simplify solving the puzzle, via cell M2

3)  Optional prompting can highlight possible squares where a number can [or must] be safely input.

4) Tip: You can input several numbers in a square and use Sure/Unsure to size them and ignore the Error message, it may help for pairs

Optional prompting updates a separate table with "pencil marks" [possible numbers that can be input in the corresponding square].- extended in version 4.10

Immediately obvious false inputs are signalled with an "Error" indication.

Latest Download xls file  (211k)   which contains a partially completed table

[After download, right click properties and unblock the file before opening
Open the file with Excel and accept to run macros or it will not work]

See the full rules and information in the Rules tab of the Excel workbook

 * Some older Office systems received an update that broke the control buttons

(current version V3.70, May 2024)