The New Sudoku Players' Forum

[Big Al]

I've learned a lot at this site. I'd like to share a paper-based technique for you traditionalists.

I created a form in an Excel worksheet. It has all nine numbers contained in each (single) square. I then use a sheet of acetate (like that used for transparencies) over it. I begin with circling the "base puzzle" values with a black dry erase marker (fine point). I then eliminate (cross out) all matching numbers for row, column, and quadrant. Then, using a blue marker, I then do the secondary selections for obvious situations.

Each number has a small space beneath it. This allows me to make notations (in letters) for certain choices. If I get trapped, I can regress back to a point of conflict, switch values, and progress (go forward) again.

The dry eraser technique allows for a lot of erasing, quickly and easily. One style of marker has a special eraser on the cap. The disadvantage is that markings can be easily rubbed off. As an alternative, one just print the grid on paper and use regular markers along with a pencil/eraser.

Al

[emm]

Hi Big Al, I’m not sure quite who the traditionalists are or if I’m one of them but do you mean old die-hards who still use pen & paper and resist computer solvers? I know some who do that, I’m just not sure that they are the same ones who would choose acetate and eraser-topped markers. It doesn’t really sound like traditionalists to me - you may have discovered a subgroup.

Everyone has their own technique and I suspect these will keep on changing with the passing of time and the solving of another few hundred puzzles. If you’re interested in my progression - I’ve gone from the grid that looks like a dog’s breakfast with holes where I went in a bit too often with the eraser, to using the fewest marks possible even if takes a bit longer. The whole business of candidate marking has become rather passé in my repertoire - it’s now the more I can do in my head, the more pleasurable the process. Hey, if Sudoku doesn’t mirror life!

[xsiveone]

I have an excel spreadsheet form also. I'll share it if anyone is interested. I created a full page sheet so I could fit the numbers 1-9 in each square without having to use a 4 pt font. My eyes have trouble focusing on small fonts these days. Anyway, I use it like the old Iowa Basics Tests from way back, you know, "two No. 2 pencils" and fill in the circles completely. I use a big marker to write the initial numbers. Then I pencil over the small numbers as they are eliminated. When I solve a square I use a different colored marker to write over the pencil marks. This allows me to tell what the original grid was. I keep notes at the bottom of the sheet, date, solve time, puzzle source, anything else that was unique about that puzzle.

[Cec]

"..If you’re interested in my progression - I’ve gone from the grid that looks like a dog’s breakfast with holes where I went in a bit too often with the eraser, to using the fewest marks possible even if takes a bit longer...."

Couldn't help laughing when reading this because it reminded me how my newspaper grid usually finished up. Except for the "easy" puzzles I confess to still needing pencilmarks shown.

".. I created a full page sheet so I could fit the numbers 1-9 in each square without having to use a 4 pt font. My eyes have trouble focusing on small fonts these days.."

Hi xsiveone,
This seems a similar method to that which I used for a while until I discovered through this forum that there were alternative ways to simplify showing the pencilmarks. We all have our own ideas as how to best solve these puzzles and there are various programs which automatically show the pencilmarks after loading the "clues" (given numbers) into the program of your choice. This removes the tedious part of including these pencilmarks thus leaving more time for the more interesting part of solving the puzzle. For me, I find this Link (just click on it) produces a neat grid, including pencilmarks and hints, and when printed is easier on my eyes whilst solving the puzzle. When I need more help I prefer to use Sudoku Solver

Cec