[CJefferson]

Generally people solve Sudokus in almost the exact opposite way.

They do very clever reasoning (much more advanced than basically any computer sudoku solver), but very little, or no, backtracking. This is mainly because backtracking more than 1 or 2 times becomes unreasonable (do you start making hundreds of photocopies of your Sudoku?)

The reason computer solvers don't do the advanced reasoning which humans do is it turns out it isn't worth it -- by the time you find and apply the reasoning, you can have done a few million backtracks, which will usually have solved the problem anyway.