Would. You. Like. To. Play. A. Game?
November 10, 2005 12:59 PM   Subscribe

For those who tire of the usual paper and pencil-based puzzle, try Websudoku.
posted by Rothko (42 comments total)
Neat, it even has pencil marking.
posted by smackfu at 1:13 PM on November 10, 2005

I've been printing up three or four of these puzzles a day for the past few weeks to keep me company during long reference shifts. Great site.
posted by robocop is bleeding at 1:18 PM on November 10, 2005

There are also these sites:

USA Today Sudoku

Milwaukee's Journal Site
posted by Qubit at 1:52 PM on November 10, 2005

Sudoku would make a kick-ass Nintendo DS game.
posted by BaxterG4 at 2:16 PM on November 10, 2005

I used the "How am I doing?" button to cheat. Why? It is my nature . . .
posted by jenovus at 2:21 PM on November 10, 2005

I have tried and tried and tried to find anything but total frustration in these....ARGH. Why aren't the fun??
posted by tristeza at 2:28 PM on November 10, 2005

Thanks Rothko.
posted by bardic at 2:28 PM on November 10, 2005

This is hard as (censored) ... I'm using trial and error combined with the "how am I doing?" button.

Two questions:

Is there a simple strategy for solving these?

Can a given sodoku have more than one right answer?
posted by alumshubby at 2:29 PM on November 10, 2005

Rothko: I thought this was already posted here, at least in the comments.

Alums: Simple strategy? For the easier ones, I first go from 1 to 9 in each set of three (across, down, etc), looking for sets of two and figuring out which ones I can block out. Then I try to line up the lines, starting with the ones that have the most filled in.

And no, a given Sudoku can't have more than one right answer, because they should give you enough to block out all others.
posted by klangklangston at 2:33 PM on November 10, 2005

Yay, I've been looking for a sudoku to play online that didn't require a sign-up and can be played from the keyboard.

alumshubby: I think that the sudoku puzzles published generally have a single, unique solution. Obviously, some set-ups have more than one solution (the empty board, for instance); others might have no solutions (a row and a column filled in except for where they meet, with all 9 digits appearing at least once)

In the case of the "easy" puzzles on that site, I am guessing that there is always a square that you can fill in by simple elimination. With harder puzzles, you might be required to make several guesses at the same time (in these four spaces I can put 1, 2, 3, 4 in any arrangement I like, but only one of the possible arrangements leaves me a solvable puzzle) or backtrack (I could put 3 or 7 here, let's see what happens if I put 3).
posted by jepler at 2:38 PM on November 10, 2005

Rothko: I thought this was already posted here, at least in the comments.

If so, I apologize. I searched Yahoo for FPPs, though, and all of them linked to paper-based puzzles or for-fee puzzle websites.
posted by Rothko at 2:38 PM on November 10, 2005

Sodoku Solver by Logic.
posted by alumshubby at 2:44 PM on November 10, 2005

I've never been able to sit at this game for more than 5 minutes. Does that mean I'm dumb?
posted by es_de_bah at 2:49 PM on November 10, 2005

I have been loving this site for a while. Nice bonus is that after you have completed a puzzle (with no errors) it will tell you where you stack up relation to other people who have done the puzzle. I have never gotten mush higher than the top 30% in terms of speed. Not sure how people are getting in the top 5-10%. My ego would like to think that they are cheating (printing the puzzle, pausing the puzzle, and then just filling it in online) but there are some serious sudoku players out there.
posted by Dr No at 2:52 PM on November 10, 2005

A couple more that allow taking notes above the value (necessary for a keyboard game).
posted by muddgirl at 2:52 PM on November 10, 2005

If you have a Series 2 TiVo and a broadband connection, you can play Sudoku on your TV.

There are a few other TiVo HME applications there too:
- Yahoo! Weather RSS feed -- Simple weather screen from !Yahoo by Alan Nickerson
- Hot or Not -- TiVo version of the Hot or Not website by Bob Pony
- PonyPoker -- A video poker game by Bob Pony
- SkullBones -- A Sample game app from TiVo.
- Sudoku -- A logic game from japan by Carl Haynes
posted by surlycat at 2:56 PM on November 10, 2005

Yeah. I'm just getting into Sodoku and it is a simple logic problem. I was so happy the first time I solved the websodoku Easy puzzle in 35 minutes until I compared my time and found that average is something like 7 or 8 minutes. *sigh*

What is the difference between the Easy, Hard and Evil? I know you get less numbers to start with, but beyond that is it still solvable by logic or do you just have to do brute force trial and error?
posted by spock at 2:59 PM on November 10, 2005

klangklangston, thanks for trying to help, but I'm just not getting what you're trying to tell me -- do you mean you test-fit pairs of missing numbers?
posted by alumshubby at 2:59 PM on November 10, 2005

spock: From the site, "Each Sudoku has a unique solution that can be reached logically without guessing."

They also link to the Wikipedia entry which discusses several algorithms.
posted by knave at 3:08 PM on November 10, 2005

Man, I'm slow at these. I need to eat more fish.
posted by bardic at 3:14 PM on November 10, 2005

No Sudoku should ever require backtracking or guessing. They're pure logic. If it does, it's a badly formed puzzle.

There are some decent solving tips on the Times Su Doku page.
posted by jacquilynne at 3:25 PM on November 10, 2005

Crap! 29 minutes, 14 sec...and that's for an "easy" one.
posted by alumshubby at 3:27 PM on November 10, 2005

alumshubby: here's some tips adapted from the NYP book I bought. let's call each of the smallest squares blocks. a row of blocks we'll call a "row," and a column of blocks "column." now, a square of 9 blocks is a group. three groups across is a "group row" and three groups up'n'down is a "group column." now that there's a bit of terminology set out, a simple strategy is to start by looking for pairs of given numbers in group rows and group columns. if there are two 2's in a group column, you can infer which column the 2 will be in for the third group. cross-reference the group row to see if you can figure out which block in that column has the 2. try to solve group rows and group columns at a time, rather than skipping around the entire puzzle.

did that make any more sense?
posted by carsonb at 3:30 PM on November 10, 2005

also, this is rad. thanks Rothko.
posted by carsonb at 3:33 PM on November 10, 2005

jacquilynne: I based my remark about "backtracking or guessing" on the description of a sudoku implementation called solo:
Difficulty levels are judged by the complexity of the techniques of deduction required to solve the puzzle: each level requires a mode of reasoning which was not necessary in the previous one. In particular, on difficulty levels ‘Trivial’ and ‘Basic’ there will be a square you can fill in with a single number at all times, whereas at ‘Intermediate’ level and beyond you will have to make partial deductions about the set of squares a number could be in (or the set of numbers that could be in a square). At ‘Unreasonable’ level, even this is not enough, and you will eventually have to make a guess, and then backtrack if it turns out to be wrong.
The distinction between performing several levels of deduction at once, and guessing/backtracking seems like a subtle one to me--is it just a matter of what you hold in your head versus what you commit to paper or the screen?

There are a lot of neat puzzles in this guy's puzzle collection, including many I hadn't seen elsewhere. Unfortuantely, the last time I checked the sudoku game was not at all keyboardable.
posted by jepler at 3:48 PM on November 10, 2005

carsonb, thanks...I assumed you meant a "row" or a "column" is three "blocks" wide or tall respectively, and a "group row" or group column" is nine...right?
posted by alumshubby at 4:02 PM on November 10, 2005

Say, for example, I have two squares, and I know they could both be either 1 or 2, and nothing else. To my mind, guessing or backtrating would involve deciding 'I'm going to assume this one is 1 and see if I run into an error that way'. If 1 causes an error, it must be 2, so you go back and change all the answers you assumed based on the 1 to what they would be based on the 2. In a properly formed Su Doku, that sort of thing should never be necessary, it should always be possible to work around to figuring out one of those squares based on other information, without ever having to guess like that.

There are levels of logic, the simple transposition of 'this is the only square in this block that could be a 9, so it must be a nine' or 'the only number this could be is a 9, so it must be a 9'. I try to get as many of those as I can out of the way first.

Then I start to look for instances where I have pairs that match. If you have two cellss in a row, column or block that each contain only the same two values, no other cells in that row, column or block can have those two numbers (since obviously, those two numbers will be used up to fill the two cells in question). In the simplest example a row with possible values 12 12 123 | 345 345 456 | 678 78 678 ..., you know that the value of the third entry must be the 3, because the 12 12 combination used up the one and the two. This scales up to three / four and more values, as well. Any time you can isolate a set of cells within a row, column or block, that contain precisely the same number of options as cells, in whatever combination, you know that nothing else in that row, column or block can use any of those numbers.

I don't actually do regular Su Doku so much anymore, as I've found the ones that the Times publishes as 'Killer' to be much more entertaining. Not harder, necessarily, just more interesting, logically speaking.
posted by jacquilynne at 4:08 PM on November 10, 2005

mmm, no. a row is nine blocks wide, one block tall. a column is nine blocks tall and one wide. three blocks across or up/down doesn't have a name, err, maybe 1/3 of a group. a group is three blocks on a side--nine altogether. a group row is three blocks tall and nine wide, a full third of the entire puzzle. same goes for a group column, respectively.
posted by carsonb at 4:12 PM on November 10, 2005

To the folks who are worried about their times:

I've been totally addicted to this site for the past few weeks. I play on 'evil' and my times are (on average) substantially longer than average.

Oh, and a few years ago I placed 16th on the US Puzzle Championship [USPC]. Which places me substantially above average for people who were big enough puzzle geeks to bother entering.

I figure our brains differ in how well they solve different kinds of logic problems. (Or at least that's how I justify my sub-standard performance....) Or, maybe, the next time I actually have time to compete in the USPC I'll find that legions of newly-minted puzzle solvers are waiting around to trounce me.
posted by Mr Stickfigure at 5:09 PM on November 10, 2005

Wasn't this one of the links in the LAST Sudoku fpp? I distinctly recall trying this site out awhile back.
posted by nightchrome at 5:13 PM on November 10, 2005

I've been digging this website for a while, the average times are really creeping up there to ridiculous levels. I still beat easy and medium a bit faster than average but can't keep up on hard. I wonder how much is due to cheating and how much is do to the really good players playing really often.
posted by I Foody at 7:15 PM on November 10, 2005

Nightcrome and Rothko: I thought so too, but I haven't been able to find it anywhere. I do know that this Sudoku was linked through one of the websites that was a posted (one that was a guy's sudoku program and also had a bunch of links to other sudoku sites) because that was how I found this one (and decided it was the best).
But there's no acrimony, Alex. It's a great site, and if it helps more people get into Sudoku, all the better.
posted by klangklangston at 7:37 PM on November 10, 2005

I've been hearing all the hype about this game but never played til just now. I solved the easy in 13 mins, but only because I kept checking the Koch button.
posted by CunningLinguist at 7:55 PM on November 10, 2005

Oh and (this is good).
posted by CunningLinguist at 7:56 PM on November 10, 2005

The interface provided by Sudoku Puzzle Generator seems to be far superior to the ones in the post and in muddgirl's comment. unfortunately it has to be downloaded.

I found that via a previous FPP on Sudoku: The puzzle that ate the world?!.
posted by Chuckles at 10:19 PM on November 10, 2005

Yeah I like the site, personally. I am trying desperately to resist getting sucked into this bizarre puzzle world...
posted by nightchrome at 10:48 PM on November 10, 2005

I'm a bit Sudoku'd out now after 6 months, but love the new 'Killer Sudoku'.
posted by Frasermoo at 1:27 AM on November 11, 2005

I find it much easier if I take notes as I do them... like, I'll go down a column or across a row, and determine "Ok, this square can be 1 or 2. This one can be 1 or 3. This one can be 1 or 4 or 5". It makes it much easier to find a lot of values, and generally you run into strings of a bunch of squares as soon as you find one. But my sudoku solutions end up being quite messy with all the notes :)
posted by antifuse at 1:37 AM on November 11, 2005

Miniclip offer a different easy, medium and hard puzzle daily, with square marking capability.
posted by biffa at 2:31 AM on November 11, 2005

Very nice site, thanks.
posted by teleskiving at 2:45 AM on November 11, 2005

I want to try one of these killer sudokus but can only find articles/examples with no good interface for solving. Is there a site that will allow me to solve online?
posted by duck at 9:10 PM on November 11, 2005

I was doing sudoku at the bus stop yesterday and listening to music when my bike was stolen. DAMN YOU, SUDOKU!
posted by carsonb at 7:47 AM on November 16, 2005

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