11 November 2006

Sudoku Tips

Sudoku Tips from sudoku.org.uk: 
This tip comes from Telegraph solver David Brook:

I think my tip might help solvers a lot. It is a little laborious the first time, but the gains are enormous. The Impossible Diabolical in the Sudoku Experiment took me about 2.5hrs utilising my method. My tip is to set out nine grids using blank worksheets. Allocate one grid to each of the values 1 to 9 and work from there. Eg, say the given starting grid contains a 5 at grid point 2,3, then working on the new “5” grid one can blank out all of row 2 and all of column 3 and all of square 1. Then you can blank out the 2,3 grid point on the other 8 grids. Proceed in this way for all the given data and the subsequent steps in the solution become much easier to see - and the ‘what if’ thoughts easier to remember.