Sudoku Re-visited

As I suspected when I ranted about Sudoku, many people have strong opinions about that pasttime. Eric's Uncle Mel, a retired math professor, wrote me such a good letter that I thought I'd post it as kind-of a guest blog:

"Do you like to climb mountains? Why do people climb mountains? I have heard that it’s just because they (the mountains) are there. Is there any physical satisfaction in climbing a mountain? I am sure there is. Is there mental satisfaction in doing so? I am sure that some would say yes. If you ever spent several days climbing a mountain would there be any satisfaction at all.

Some people enjoy life by doing complicated tasks. Others do simple tasks and there are many examples of both simple and complicated tasks, too many to even go in to.

Now some say that doing Sudoku is too simple to waste one's time on. One person told me it’s too much like Math 101. Others take great pride in being able to solve even the simple or easy ones. It so happens that my brothers, my sister and I like to do Sudoku. Learning the techniques that one must use to solve each one is very fascinating.

Some say it’s too mathematical but let me assure that there is very little mathematics involved. Change the 1’s to A, the 2’s to B, the 3’s to C and so forth and where is the Mathematics? The only mathematics is really the “Pigeon Hole Principle” The Pigeon Hole Principle is easy to understand. If you have N items to put in N Pigeon Holes then it is possible to put exactly one item in every Pigeon Hole and it will exactly fill up every hole with exactly one item. Pretty Basic, right?

So here we have nine items, the numerals one through nine. You could say they are numbers but they are really the numerals representing the numbers 1-9.

Now we must put each of the numbers in the Pigeon Holes so that :

a. Each numeral appears in each row exactly once

b. Each numeral appears in each column exactly once

c. Each numeral appears in each 3 by 3 square exactly once.

Supposedly, the composers of the puzzle include enough numerals to start so that the solution can be made in only one way.

These puzzles can be done while watching a sporting event on TV. One can watch the TV, do the puzzle and not miss one play. A person who is unable to read on a plane or in a moving car because of the motion can do Soduku. Of course, one will miss the beauty of God’s earth, while traveling, but that does not matter if driving across parts of Texas. I suppose some might even attempt to do one while listening to a sermon in Church but I would not even suggest that.

Now some of these puzzles are harder than others but I have not been stumped one a 9 by 9 one yet. They are supposed to be able to be solved with logic and not trial and error. There are two that I have had to use trial and error and this bothers me. I must be missing one of the clues but I will keep looking. I also have a friend who will use a pencil only to put the final numeral in the box. He will use no possible list of numbers in each box as my sister and I do. You should not do these if they frustrate you because I will just go on entertaining myself."

Of course--he's a math genius, so the annoying little puzzles are easy for him! But he's also a sweet, loving man, so I know he's sincere, and if I get stuck on one I could always call on him for help. Also, I've actually done quite a few more Sudoku since Bobby has been in the hospital so much, and I've come to enjoy them. But only if they are labeled "Very Easy" or "Easy."