ECOURSE PART 2: SOLUTION METHOD-SCANNING

Scanning is one way that you can solve a Sudoku puzzle. When you first look at that puzzle you should scan it at least once and again a few times while you are trying to arrive at the solution. Take some time to analyze the puzzle as you are working it since scanning can help you to quickly pick up on a working in one or two needed numbers.

There are two basic techniques when it comes to scanning: cross-hatching and counting. You can use both of these methods alternately.

You won’t be able to scan the puzzle any further when you run out of numbers to put into cells. After this you will need to start working the puzzle from a logical stand point. Some people find that it helps to mark possible numbers in the cells. You can do this using either subscripts or dots:

• Subscript marking: Use subscript to mark possible number into the cells. The one disadvantage to this is that many puzzles, such as those found in newspapers, are often too small to allow you to write in the cells. Consider making a larger copy of the puzzle so that you can read it easier or use a pencil that is very sharp so that you can write fine lines.
• Dot marking: Dot marking involves using a pattern of dots. A dot in the top left will indicate a one and dot in the bottom right will indicate a 9. The advantage of using the dot notation is that you can easily use it on the original puzzle. You will have to make sure that you don’t make a mistake with the dots or you will be led into confusion and it may not be easy to erase dots without creating more confusion.

Next time we'll be discussing alittle about "Beginning the challenge".