We were going to spend ten days in St. Barts, so when we stopped by a pharmacy to pick up the essentials, I perused the newsstand for some interesting literature. A small Sudoku puzzle book caught my eye. “Why not?” I asked myself. After all, I know math. I even published a statistical theory article once. Not that I was really all that interested in solving puzzles—I had long since grown out of that—but it would be interesting to see how it worked. Furthermore, it was the spring of 2005, Sudoku was all the rage, and I wanted to see what it was all about. My interest, though, was in the actual solution process, not just the challenge of solving a puzzle. Besides, the cover proclaimed in French: Simple et Moyen (Easy and Moderate).
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It took about a year to put together my basic system, and I knew there were still some missing parts. I posted my findings under the title Rational Sudoku to contrast it with the other solution strategy, which I now call the “Standard Strategy”—the basis of which is known as the “Possibility Matrix.” It is a process, for those lacking a solution, in which all possible solutions are marked in each vacant cell of the matrix by placing little marks representing the
Once we had settled in at our destination, I began my first Sudoku: Simple #1. Little did I imagine that it would captivate me and forever change my life. I struggled with that little puzzle for over a week. Each day, I returned to where I had left off, and each day my frustration grew—along with my determination. “I will solve this #*@% puzzle,” I kept telling myself. “I am bigger than this.” Finally . . . success! I had solved my first Sudoku. Still, it injured my scientific ego to think that it had taken so long, and although I had gained some insights into the process, I was still very far from understanding it. On to puzzle two—this time a Moyen. I was still working on it on the plane back to the States. My insights grew with each correct digit I placed in the matrix, but I was still far from putting it all together, and my patience was running thin. So, I went to the Internet and ordered three books on how to solve Sudoku. When they arrived, I tore into them like a hungry wolf. I didn’t really want to read them and see that someone else had figured this all out, but “Enough is enough,” I thought; I was about to throw in the towel. What I found in those three books both horrified and emboldened me. I had already formulated the rudiments of a solution strategy, and what I read offered no threat to my ideas or approach. On the contrary, I couldn’t understand why anyone would want to make the solution process even more complex! Trying to apply the books’ strategies to any given puzzle literally gave me a headache and generated massive confusion: trying to work through the logic of it was confounding. Therefore, I promised myself that I would not look at another Sudoku strategy book until I had worked through all my own thoughts on the matter. So, I started working on puzzles on WebSudoku.com and felt like I was making progress. But I was in disbelief at how fast other people were solving Sudoku on this site. I even inquired as to whether or not their time logs were real—and they were, according to the Web Sudoku folks. I plodded on.
missing digits. I refer to them as “digits” because they are not always numbers, and they could be replaced by letters, geometrical forms, baseball logos, etc. My grandchildren, in fact, used to solve simple Sudoku using SpongeBob SquarePants stickers. The point here: Sudoku has nothing to do with mathematics and everything to do with logic and reason. This was the appeal to me—logic and reason. Thus, what was the logic that formed the foundation of Sudoku, and how did one reason through the solution process?