Good morning,
I suggest you discover a site that I have just developed: http://sudoku06.fr
It allows two things:
1) solve a grid manually, possibly with clues offered by the computer in order to progress when you are stuck
2) ask the computer to solve a grid step by step, that is to say as a human would do
It seems to me that it is a very useful tool for progressing in the knowledge of resolution techniques. In addition to basic techniques, this tool manages techniques such as X-WING, XY-WING, single rectangle, forcing chains, coloring, Swordfish. When none of these techniques complete a grid, brute force is used.
Brute force is never really satisfying. I would like to develop other solution techniques to avoid this technique. If you have any ideas...
There are three ways to enter a grid:
1) manually
2) by level of difficulty
3) by predefined grids (which allows you to better understand complicated techniques)
It is possible to select the permitted techniques. Always with the idea of becoming familiar with them.
Finally, the site is completely free. I have nothing to sell!
Good day,
Michel B.