Teach Yourself Sudoku

Learn the secrets that let you easily solve Sudoku puzzles faster!

Lesson #7. When you SOLVE a number in a cell, immediately erase ALL other occurrences of that number in its associated RCB. Do your Housekeeping!

 

OK, this sounds simple but my emphasis is on the ALL.  You have to be thorough about checking all of the parts (Row, Column, and Block) that are associated with the Cell you just solved.

 

Well, why wouldn’t you do that?  Sounds obvious, doesn’t it?  The most common reason is that you see another cell that you can now solve so you forget about the number you just solved and the process of checking its associated Row, Column, and Block and move on to the next cell.

 

Don’t.  Or at least try your best to resist the temptation.  It will save you so much time later on.  If you’ve never played Sudoku, you might wonder how you could NOT do this.  “Just take your time and check everything.” you say.  However, anyone who has actually played even just a few Sudoku puzzles knows that you can frequently find our self in a flurry of solving one number after another  and you’ll find yourself scrambling to erase and rewrite and erase and rewrite as fast as you can.

 

If you get sloppy about this, here’s what will happen.  You’ll eventually get stuck.  You’ll be unable to solve any other Cells.  Every place you look, you’ll determine that it is impossible to make any progress.  You may find that being “stuck” is just too frustrating and you decide to move on to the next puzzle.  Or you’ll have to take every solved number and one by one, go through every Row, Column, and Block and manually check to see if it has been erased properly from all of the associated RCB cells.  Yuck!  Not fun and very time consuming (but if done properly, it will but you back on track to successfully solving the puzzle.)

 

If you have never experienced having to doing this, you will if you continue to play to Sudoku.  So why not minimize this chore by making sure that before you move on to the next Cell, you’ve thoroughly completed your Sudoku Housekeeping!

 

 

NEXT UP: Lesson #8.  TEAMS

 

Copyright 2006 Gary Ward All Rights Reserved