Friday, October 5, 2007

How to Play Sudoku: Tips and Tricks, Lesson 1.1

Sudoku Basics

For a different challenge, try The Greatest Maze on the Web

Before Learning Sudoku

Before we begin, make sure you are familiar with the basics of Sudoku: puzzle rules, how to play, how to win - yes, those are, basically, the basics. For the benefit of everyone, Sudoku Tips and Tricks has provided you with exactly the bare-bones essentials you need. Go ahead. Check it out. Take your time. When you're ready, please come back and join us in the classroom.

Sudoku: Rules of the Game

Go on, don't be embarrassed. We promise not to tell anyone.

Tips and Tricks: Sudoku Lesson 1.1

Sudoku Lesson 1.1Okay, Sudoku white-belts: we are ready to begin. On the right, labeled Sudoku Lesson 1.1 - Game 1001 is an example of a fairly simple Sudoku puzzle. For those of you who studied our Rules of the Game (see above) or have already completed Free Sudoku Novice Puzzles: 1001 - 1002 this example will probably look a little familiar. For the rest, please feel free to give the image a click: we will open the puzzle in a spankingly new, exhilaratingly printable window. Spank and print away at your leisure.

There are as many Sudoku puzzle strategies as there are stubborn knuckleheads in the nosebleed section of Fenway Park - yes, perhaps even more than that. Most average Sudoku gamers usually follow the beat of their own drum: they just plow through the game, trusting to their wits; or worse, with their sneaky pencil they will add a number to the Sudoku puzzle before they have uncovered the solution with 100% certainty. Honest! Some Sudoku gamers will stoop so low as to guess. Don't be distressed. We will teach you our step-by-step method with which you can change the Sudoku world for the better.

Step 1.1: Sweeping the Sudoku Board

Cleaning up the Sudoku board is always the first thing to do when beginning a puzzle. You should also make sure (don't forget!) to clean the board after every future step of our Sudoku method. This is how you do it:

Sweep the board numerically. Imagine that every number 1 is like a tiny sun, whose rays sweep across the board. Mentally sweep horizontal and vertical lines from every number 1 all the way to the edges of the Sudoku board. All of the squares that your lines sweep through are spaces that no other number 1 can live, in accordance with martial Sudoku law.

Sudoku Lesson 1.1: Good Mental SweepPay particular attention to those 3x3 Sudoku boxes that are quite dirty already - those boxes that have many of its squares already filled with other numbers, but are still missing the number 1. Using the Sudoku sweep technique on our example to the right (again, feel free to click and print), you will see that two 3x3 boxes only have one remaining clean square. That square, in each of the boxes, is clean enough to become a number 1.

Sudoku Lesson 1.1: Dirty Pencil SweepNow, before we proceed, we want to return to our favorite hobby horse: mental solutions versus pencil solutions. Perhaps you are the dutiful, diligent sort of student who printed out our example when we made the suggestion. Perhaps you have followed along with the lesson by making nice long sweeps with your pencil. At the moment, perhaps, your printout looks something like the cluttered, dirty pencil-sweep example on the right. For shame.

It is very important to get in the habit of doing these sweeps mentally. Please try not to draw on the Sudoku board unless you are writing down a happy, clean number on the grid. Remember: this is only Step 1.1 and we have only uncovered two new number 1s. There simply isn't room for pencil clutter within our Sudoku method. Think how impressed that slob sharing your subway seat will be when you are able to solve the puzzle without soiling your Sudoku pages.

Your first assignment: Using the sweep method, sweep the entire board numerically, all numbers 1 through 9. Try to curb your enthusiasm and use only the sweep strategy. Do not fill in obvious numbers if you didn't sweep them out. Let's see where this leaves us when we're through.

Finished? Check your work here:
Sudoku Tips and Tricks, Lesson 1.1 Walkthrough

Bag O' Tricks: Sudoku Links

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