enxio27 wrote:Following with interest. . .
While I have your attention, I visited the site, and I have a question. What is "compass" sudoku? I didn't find any explanation of how it works.
Some 5-7 years ago, I encountered something called "Color Sudoku" in a newspaper. Each of the nine cells in a box were a different color and the addition constraint is that each color must have all digits from 1 to 9, just like the other houses (rows, columns, boxes).
While creating these color sudokus was not a big problem, it turned out that solving them on paper was hard because of the layer of color that the laser printer had applied. The ink did not stick so well.
So I went looking for a different visual representation and opted for the "Compass" flavor: Each of the cells now is assigned a direction (not surprisingly called NW,N,NE, W,Center,E, SW,S,SE) and each direction must have all digits 1-9. It is easier on the eye than those crazy colors and it is also easier to write down NW, SE than "pink", "orange"
Hope this explains what Compass is.
Why do I like the Compass puzzles so much?
They force the brain to work on one extra dimension. We are all so used to the 9x9x9 square and the well established ways of solving these puzzles.
With Compass I went back to solving with basics only (no fishy business there, no wings either), but with another "house" to keep in mind, one that is spread across the whole grid. It is MUCH more difficult to recognize a naked pair in NW than to find a quad in a Classic Sudoku row or column or box.
As I like to do my daily Sudokus at breakfast, I found out that most of the "Very Hards" with xy(z) wings take me something like 15 to 25 minutes. The Compass Sudokus usually take around 45 minutes. Basics can be quite exciting