In this exercise, we take another shot at lookahead. This puzzle is somewhat more difficult than the last and will illustrate just how frustrating doing alternate routing can be. It will also take on...once again...the seeming paradox that choosing the WRONG path may sometimes be more productive than choosing the right, however frustrating it might seem to run up against a dead end after working out most of the puzzle.

As mentioned in the last lesson, after finishing this one you should be able to take on ANY Sudoku puzzle and solve it. In fact, the main point of these lessons has been to teach you to understand all the ways you can use simple logic...actually simple elimination...to solve Sudoku puzzles.

So...keep on keepin' on...you're almost home...