Implementation
 

The aim of this website is to serve as a playground for anybody wanting to improve his skills in solving sudoku puzzles. Particular emphasis is put to visualise graphically the logic at the base of the solving strategies.

 

It suits equally well the needs of a beginner as that of an advanced player thanks to the preferences menu.

  Features
 

  • Entirely controllable with the mouse pointer
  • Input a puzzle of your choice or let it setup by the program
  • Hints available if you get stuck
  • Graphic highlighting of the rules
  • Move history with Undo/Redo

  Rules
 

A sudoku puzzle consist in a square matrix with 9 rows and 9 columns to be filled with the digits 1 to 9

 

in such a way that each one appears only once in a row or a column and in any of the nine (3 x 3) regions.

  How it works
 

In setup mode you can fill in an empty grid with a given sudoku puzzle by clicking the digit in the corresponding cell. Use the undo button in case of an error. Alternatively you can let fill in the grid with a puzzle by the program itself. If you click on a filled cell all cells with the same digit will be highlighted in a purple shade.

 

If "show candidates" is ticked all empty cells having the digit as candidate will be highlighted by a green shade or, depending on the setting in preferences, the cells not having the digit as candidate will be highlighted by a reddish shade. If you ask a hint a cell that can be uniquely filled will be highlighted for a short period by a yellowish shade.

  Playing
 

You can adapt the size of the displayed grid by rotating the mouse wheel while keeping the Ctrl key pressed. If you want to use it as a training ground try to solve your chosen puzzle without the "show candidates" mode.

 

At any moment you can switch the display mode, and if you get lost you still can ask for a hint to see what could be done next. Try to find out what logic justifies a given move.
Well that's all, enjoy now!