How to solve Sudoku puzzles

There are many webpages on how to solve Sudoku puzzles, and I've read most of them. I use some of these techniques, but many I find a waste of time. Some techniques work only on easy puzzles and some require too much writing down of numbers. Some techniques are useful but only rarely. When I solve Sudoku, I use four strategies that together will solve almost any Sudoku. A "box" is a small square that can contain one number, a "square" is one of the nine sections that can contain nine numbers. The video demonstrates each of these strategies several times. 1. Cross hatching and Slicing and Dicing, two different ways to look at the same thing. Pick a number and a square that does not contain that number. In that square, any box that has that number in the same row is eliminated, and any box that has that number in a column is eliminated. The remaining boxes in that square are the only boxes that can contain that number. I usually start a puzzle with the number 1, and cross hatch each square looking for that number, then the number 2, and so on so I don't miss a number. 2. Either/Or. When "in a square" a number can fit in only two boxes, I write that number down in the lower part of those two boxes. I ONLY do this when those two boxes are in the SAME square. 3. Pairs. When two numbers can only go in the same two boxes, I write those two numbers down in the upper left corner of those two boxes. These two boxes then form a Pair. For Pairs, the two boxes DO NOT have to be in the same square, but the two boxes are considered a Pair only if they are in the same square, row, or column. 3b. Half Pairs. Sometimes I find that a particular box can only contain two numbers, I write these two numbers in the upper left corner of that box and call it a "half Pair". I often later find a matching "half Pair" in another row, column, or box to form a Pair. 4. When a row, column or square has 4 or more numbers known, the list of remaining possiblities is checked for each of the vacant boxes in each corresponding row, column and square. If all but one of the list is found, that number is the solution for that box. If all but two of the list are found, those two numbers form a "half Pair". Each time I write down an Either/Or or a Pair, I am writing down information in an easy to read format for future reference. Finding a Pair does not just tell me about those two boxes, but it also tells me that none of the other 7 numbers can go in those two boxes! This constant buildup of information leads to finding more information and then the numbers themselves. If I get stuck, I first go back and (1.) cross hatch for each number in each square, then try (4.) again. Then I look for triples, but this is rarely needed. Almost all Sudoku puzzles can be solved using only these four techniques. The "Fiendish", etc. puzzles may require checking for "triple" or some other advanced techniques. The video demonstrates the use of these four strategies with a non standard Sudoku that appears to be difficult. It is non-symmetrical and has only 17 numbers to start with. To demonstrate how the remaining 73 numbers are found takes 14 minutes, over 5 per minute, so you may need to stop the video now and then to be sure you understand how each number is found. As with any Sudoku system, you MUST write each number down correctly. A single incorrect entry may render the puzzle unsolvable, so check twice and write down once. This video was taken with the Panasonic PV-GS35 Sailing Video Index

Broadband users can just left click on the picture to see the video with Windows Media Player. Dialup users should right click on the picture below and select "Save Target As" to save the video on your hard drive because the video will take longer to download than it takes to watch it. After downloading you can watch it without pauses. Broadband solve Suduko video, Puzzle #1, 19 MB Broadband solve Suduko video, Puzzle #2, 15 MB