A simple method of resolution

Enter possible candidates

To enter candidates simply click in the small gray square in the upper left part of each box. The commands will appear in gray. Take note of every possible digit for each box. In the first region, insert these candidates from 1 to 9 in any possible square. If the digit is already present, proceed to the next region. You must take into account the single digits in other regions that block certain squares and thus limit the number of candidates that may be placed.

Important

Take time to verify this first step to be sure to have noted all possible candidates. A misplaced candidate can cause inconsistencies thereafter!

Exclude unsuitable candidates.

The aim is to phase out all possible candidates, such as candidate 7 of the image below that may be found in 3 different yellow squares.

Since the candidate is the only one placed in the green underlined square, it is obviously in the right place.

Lorsqu’il est possible de placer un chiffre unique, il faut supprimer tous candidats identiques au chiffre unique présents dans la région, ligne, colonne.