Sudoku by hand

You know, working on that Sudoku solver has really helped me when I’m solving these things by hand. Working out the algorithms for solving these puzzles has made more more meticulous when I’m doing it on paper. Not only does that keep me from making mistakes, but it keeps me from overlooking possible solutions. I also discovered a few new tricks while writing the solver. I’m still working on jsudoku solver 3, because what I’ve got is still kinda ugly and slow. But I actually like that it doesn’t solve instantaneously. It’s fun watching the numbers populate in the order that they’re solved. In case you didn’t notice, part of my algorithm involves making guesses when there’s not an obvious solution. After guessing one number, the solver will try to solve from there. If it runs into a problem, it’ll back out and try again. That’s my favorite part!
Anyhow, solving by hand.
People have different methods for solving. Personally, I have a male brain. This means I can only think about one thing at a time, so if I don’t write down every step in the solution, i get distracted by …oh, look, something pretty!
Where was I? Oh yeah. So I use the “grid of dots” method. I just made up that term. It’s like this: I imagine each unsolved box in the Sudoku is a 3×3 grid. The top row represents 1-3, next row 4-6, bottom 7-9. As I eliminate possibilities from a box, I put a dot in that box’s corresponding grid location. For example, I know that box X cannot be a 5, 7, or 9 because I’ve already used those numbers in the row, column, or 3-by-3 square. So in box X, I put a dot in the center, the bottom left, and the bottom right. When box X has 8 dots in it, I know that the solution is the number corresponding to the missing dot.
Of course, if i can’t tell a dot from a crumb, then I end up blowing the whole thing and solving it with my program. But if I’m really meticulous, this works for me, and is really the only way I can make it through one of these numbers.
Congratulations for reading this far in my ramble! Now it’s your turn for participation.
What’s your Sudoku style, trick, or method?