Su Doku - Any tips?

I do the Times Su Doku puzzle most days of the week.Times - Su Doku

I can do the easy, mild and most of the difficult but struggle with the fiendish level, anyone else do this? Tips to complete the really hard ones would be appreciated.

[Fiendish bump]

I’ve been getting into the Su Doku in the Saturday times, along with the rest of the country. I can clean them up no sweat, but it usually takes me a lot longer than the recommended time. The Samurai Su Doku at the weekends usually has a completion time listed of less than one hour, which is pretty difficult IMO. I think that the time taken is a good judge of one’s Su Doku Fu, most folk of a logical bent will complete a fiendish in an hour or two, doing it in twenty minutes is another matter. There’s probably more than a few mad (or sad) bastards out there who are perfecting their sub-five minute fiendish Su Doku technique.

I find the tips that you read on Su Doku to be largely useless, as you already know them anyway. I’ve never seen one that made me do the puzzle differently. I think this points to an eventual demise of the Su Doku craze in the UK, its hard to really chat about them, or discuss tactics and strategy. The simplicity of the Su Doku is no doubt the reason for its success, but it could lead to the puzzle having a relatively short shelf life in the papers. We shall see if people are still doing them next year I guess.

Ahhh, Sudoku. My mother growls if I go too near the paper if she hasn’t finished it yet. I bought her a book of puzzles - I am the Best Daughter Ever now.

I don’t know any specific tips - it’s just a matter of looking at the grids etc, I think. I can’t hold it all in my head, if you follow what I mean, so I struggle with the trickier medium ones.

I have no idea what tips are published in your paper (they don’t have tips in ours, the bastards), but I can tell you my “technique.”

I try to find a line or square that needs fewer than 4 smaller squares filled in. If none is available, I start with 5. I use a light colored pen and write the possibilities in the corners of the small square. I then look at the line or large square and see if there is anything I can fill in as a definite. If there is, I use my regular blue or black pen to fill it in. I can see if there’s a definite if, obviously, there’s only one square in the line or big square that has a certain digit (for instance, if in all the little squares I filled in on a line, only one contains an 8, I know that square must be the 8). I fill in every square in the whole puzzle with possibilities and use the light color pen to eliminate what I’ve written in each square while solving.

Another trick is if there are two small squares on the same line or in the same big square that each contain the same pair of numbers, I can eliminate those numbers from the other small squares. For instance, say that there are two small squares in a line that both have the only possible numbers for them as 2 & 7. Since one must be 2 and the other must be 7, that means no other square in that line can contain either of those digits.

That’s all I can think of off hand right now. I’m pretty good at them and can usually solve the harder ones in less than an hour. I’m not sure how my paper’s SuDoku measures up to yours, though.

Tips?

try filling in the squares with numbers from one to nine.

You’re welcome.

Check each column of three grids and look for numbers that are already placed in two grids. At most, you’ll have three possible squares where that number can go in the third grid. If you’re lucky other clues will eliminate two of those squares. Do the same with the rows.

http://boards.straightdope.com/sdmb/showthread.php?p=6362337#post6362337 (post 18)

Mrs. Nott plays them at http://www.websudoku.com/ There’s an option that tells you when you make a mistake.