Sudoku

[helen]

The Star-Bulletin calls it Universal Sudoku while the Advertiser calls it su|do|ku. However you call it, you have it fill in missing numbers in a 9x9 grid. Has anyone played this yet?

[scrivener]

Re: Sudoku

The Star-Bulletin calls it Universal Sudoku while the Advertiser calls it su|do|ku. However you call it, you have it fill in missing numbers in a 9x9 grid. Has anyone played this yet?

I have been doing these for years and have collected close to a hundred of them; if you're jonesing for more, I've got some cool variations of them, too, and would be happy to send you some PDFs.

[Surfingfarmboy]

Re: Sudoku

The Providence Journal newspaper just starting publishing the Sudoku puzzles about a month ago here. It's going under one of those reader evaluations to get feedback on it.

The one newspaper puzzle I'm really jonesing for is the one the Advertiser prints..the word thing by Kathleen Saxe where you make as many 4+ letter words from a given word in a finite period of time. I love that one!

[Moto]

Re: Sudoku

I tried a couple last weekend. I found it easier to do it utilizing an Excel Spreadsheet. I found it addicting. I've always been a sucker for logic type puzzles.

[Linkmeister]

Re: Sudoku

My Mom has become addicted to it. I haven't tried it, but I'm still mad that Non Sequitur has disappeared from the comics pages, so I'm in no mood to try anything that's found on those pages.

[Surfingfarmboy]

Re: Sudoku

Okay..what's the basic beginning strategy for simply starting the solving process of this puzzle? I've tried a couple of ways which I thought were decent strategies, but came up with unavoidable numerical conflicts due to (now obvious) errors in my logic.

What's the best way for a newbie at this puzzle to get a grasp on its basics?

I worked 2 hours on a 2-star rated grid and haven't come close to finishing it yet..this is very humbling to someone one who generally can knock off the NYT Sunday Crossword in relative ease, or score at least a 275 in a decent Scrabble game.

I'm beginning to see that this game deals with something that I may be somewhat deficient in..elementary logic..the condition A is met by condition B, therefore the answer can only be C, and so on, kind of thing. I've never been any good with those logic games (usually imported from the UK, sold in the crossword sections of newsstands) where one is to derive a conclusion from a given set of discrete and independent facts.

Any help would be most appreciaated.

[lavagal]

Re: Sudoku

Surfingfarmboy:

I have noticed through the week that they are either eaiser or harder, depending on the day. Tuesdays, I always get it. Easy. Sundays are insanely difficult and nearly impossible. You must guess at Sundays at times, and it's maddening.

The sudoku box is a grid of nine boxes, into each of which you must put the numbers 1-9. As you install the numbers 1-9, they cannot repeat in the rows in which they exist either up and down or side to side.

As a result, you have nine cubes of nine numbers, nine rows of nine numbers, and nine columns of nine numbers, where only the numbers 1-9 are placed once.

Wait, there's more! There's a top row of three cubes, a middle row of three cubes and a bottom row of three cubes. There's also a left row of three cubes, a middle row of three cubes, and a right row of three cubes. Say you put the number eight in the first cube of the first box. In the next two boxes either up and down or side to side, the eight must exist in either the second or third row, in the next two boxes up and down, and side to side.

So the trick is to not to repeat a number within the subcube, or within the same row up and down.

I give myself half hour to 45 minutes to do it. For the last two nights I did it in bed, instead of playing solitaire Scrabble on my Baby Dell (Axim), to lull myself to sleep. Tuesday's was easy. I guess that's how they suck you in.


clear as mud?

[scrivener]

Re: Sudoku

Surfingfarmboy, and anyone else sorta puzzled (ha!) by the Sudoku:

I happen to be teaching one of my Algebra classes how to do these today, so just come on down at about 10:00 and join us.

Just kidding, but here's where I usually tell my students to start.

First, it's a logic puzzle, so you want to start in areas where you're given the most information. That may be a particular 3x3 square, or a single row, or a single column. The more information you have, the more possibilities you can eliminate.

Second, a good start is to write in small numbers all the possible numerals that can occupy any one square. In the easier puzzles, this usually reveals enough to finish the puzzle: This square can have a 2, a 4, or a 9. This square can have a 2 or 9. Wait a minute -- no other square gives the possibility of a 4, so this first one is the four!

After you've done a few of these, it will probably become less necessary for you to jot these possibilities down, because you'll have developed other strategies. What I love about these puzzles is that there's no one strategy that works for all arrangements. In the trickier puzzles, there's only ONE strategy that will work, and the challenge is in identifying that one strategy.

In my other Algebra class, one of my students showed me a pocket-sized paperback collection of Sudoku puzzles; it looked like an American publication, too (normally, I have to send to Japan or England to get anthologies of logic puzzles like this). This is a good sign.

Later this morning, I'll upload a link to some Sudoku variants, for those of you interested in turning this into an obsession!

[Surfingfarmboy]

Re: Sudoku

Thank you, LavaGal and Scrivener, for the information on the cracking the Sudoku puzzles. I'm afraid that I might become one of the many who have found themselves addicted to this puzzle. I've been thinking about the Sudoku puzzle I tried to deceipher last night for most of the working day, and I'm ready to take another stab at it, armed with the stategies listed. Really..how hard can it be? That's what I find so frustrating about it..it's so simple in concept, but make one mistake, and the whole grid is thrown out of balance. I'm going to arrive at the solution, no matter what it takes!!

[scrivener]

Re: Sudoku

Okay, you puzzle freaks and freak-wannabes.
I've got a couple of variants from Oekaki King and Logic Paradise, two Japanese puzzle magazines I subscribe to. The overlapping ones work the same as normal Sudoku puzzles, but keep in mind that the overlapping parts need to satisfy both puzzles.

The puzzles with > and < signs are like normal Sukoku puzzles, but without the 3x3 squares. Instead, satisfy the "no more than one occurrence" rule in rows and columns only, but also make sure that the arrangement of the numbers satisfies the "greater than" or "less than" statements created by the puzzle's design. You'll know what I mean when you see it.

A couple of the files are just regular Sudoku puzzles, in case you need more than your daily fix.

All files are PDFs.

Download the ZIPped archive of all six puzzles here,
or click
here,
here,
here,
here,
here, and
here for the individual files. Sorry about the quality -- these are passable scans, but they could certainly have been better.

[scrivener]

Re: Sudoku

Hm. Turns out there isn't just one book. Check out the search reults at Amazon.

[tiptoetulip]

Re: Sudoku

In trying to look up some other puzzles, I came across this site which has links to other Sudoku versions (mini, classic, word, color, monster): Other Sudoku versions

I am thinking my 4th graders would love to do these!

[pzarquon]

Re: Sudoku

As soon as I saw questions about this game, I thought, "There must be a Wikipedia entry..." And there is! It includes a small section on solution strategies.

[Surfingfarmboy]

Re: Sudoku

If any of you in this thread are interested, I did get around to solving that Sudoku puzzle (the one I mentioned in this thread). It took me much longer to solve that I anticipated, but I did it, and now I know the basic strategy for completing them.

The one thing I now is that one has to be certain that any number you fill into a square must be correct..one mistake, and given the nature of the puzzle, the game is lost..a mistake might not be evident at the beginning of the solving process, but it will arise, just when you think you might have the puzzle solved.

I think I'm hooked.

BTW, does anybody know how many combinations of this puzzle could exist, say with just perhaps ten numbers revealed out of the 81 possible in the 9 x 9 grid? I've been trying to come up with the formula for this, but I'm coming up blank. It's easy enough to see that 9 unique numbers can be arranged in 9! ways, but when you factor in the interlocking nature of the grids..9 up columns, 9 columns across, with x number of numbers revealed in a grid, and the fact that the 3 x 3 boxes must meet a criteria of having 9 unique numbers distributed uniquely among (9) 3 x 3 grids..how would one even begin to calcualte this? Do the makes of Sudoku have a program that randomly spits the grids out...it boggles me that they can create them at all!

Note: After writing this I went to Wikipedia link PZ provided, and I read the article. Evidently, there are programs for the creation of grids. And somebody has calculated the number of possibilities. To the guys who created these programs and did the calculations..man...they think at a level I cannot possibly comprehend!

[tiptoetulip]

Re: Sudoku YAY!

Play Sudoku Online

I finally finished my first sudoku!!!! It was an "easy" one, took me 15:59, but yippee!!

I just could not get it last night, but today, I did it!

Addictive, indeed.