Timing TBLR Sudoku

What is TBLR Sudoku, you ask? Top-to-bottom, left-to-right Sudoku, of course! It’s a Sudoku variation where the empty squares have to be filled in starting at the top row, going left to right, and continuing in that order until you get to the rightmost empty square on the bottom row.

I find it an amusing variation, because I have to recall numbers I’ve found in order to fill in the numbers in the correct order. The downside is that sometimes it takes a while, especially with the harder puzzles. Therefore I have created a compromise. I’ll spend 30 minutes trying to fill in the grid TBLR. If I don’t succeed in 30 minutes, I’ll fill in the empty squares I’m remembering, and try for another 30 minutes.

It would be really stuuupid to make a separate post for each day, but it might not be so bad to make one post per week, with the times and results for each week. Today was a particularly good day for me, as I solved a 2-star puzzle TBLR in 22 minutes, 48 seconds. That may be a personal best for me, but I haven’t done a very good job of keeping statistics. It is my plan in the coming days to keep track of my statistics in this space, and hopefully improve my times for each level of puzzle difficulty. I’ve done a 4-star puzzle TBLR in under 30 minutes, but I don’t have the exact time.

Tuesday, 11/10/09 : 2-star, 22:48
Wesnesday, 11/11/09: 3-star, 53 open squares, 5 filled in (all in the top row), 26 squares identified (that means I figured out what they were, but I hadn’t filled them in yet), 20 squares unidentified in 30 minutes. I filled in the 26 squares I identified, and took an additional 5:15 to fill in the rest.
Thursday, 11/12/09: 4-star, 53 open squares, 1 filled in, 28 squares identified, 24 unknown in 30 minutes. I filled in the 28 squares I identified, and took an additional 5:09 to fill in the rest.
Friday, 11/13/09: 5-star, 54 open squares, 0 filled in, a measly 8 squares identified, 44 unknown in 30 minutes. I filled in the 8 squares I identified, made a guess between two numbers as to what should go in a particular square, which turned out to be the wrong guess. Sad, sorry, miserable fail, but what should I expect on Friday the 13th?
Saturday, 11/14/09: 6-star, 52 open squares, 0 filled in, 19 identified. I filled in the 19 squares I identified, made a guess between two numbers, and it was the wrong guess. Fail. I’m 0 for 2 as far as guessing is concerned.
Sunday, 11/15/09: 5-star, 50 open squares, 0 filled in, 11 identified, 39 unknown in 30 minutes (An upstat of 3). I filled in the 11 squares I identified, and took an additional 28:47 to complete the puzzle (another upstat over my Friday fail)
Monday, 11/16/09: 1-star, 51 open squares, 45 filled in, 5 identified, 1 unknown in 30 minutes. I filled in the 5 squares I identified, and took and additional 0:04 to complete the puzzle. I had it figured out, and was racing to finish, but didn’t quite make it.

Since the last time I wrote about Sudoku, there’s been a couple of changes in my solving strategy. Now when I find that a number must go in a certain square, I look to see if that causes any other numbers to go in any other squares. Also, whenever I get six squares filled in either a row, a column or a 3 x 3 box, I check what’s left, as the chances are good that the remaining squares might already be determined.

I’ve noticed that after doing Sudoku puzzles TBLR, doing Sudoku puzzles the normal way is significantly easier.