They say it's the Rubik's
Cube^{®} of the 21st century! Be honest: you were never truly convinced
that we needed a Rubik's Cube of the 20th century. But who would have predicted
that one of the main reasons for people buying newspapers worldwide in 2005 was
going to be a funny little number puzzle invented in New York in the '70s? Here
in the US, we've actually been a little slow on the uptake, and the *New York Times* notably hasn't (yet)
deigned to join the party started this summer by the *New York Post*, and gatecrashed by the
*Washington Post*, the *Los Angeles Times*, et al. But in the UK,
for instance, Sudoku has officially become a *phenomenon*. (That's mediaspeak for "fad
that nobody was expecting but, hey, we're going with it, even if we're the
*Guardian*.") The excellent
Wikipedia
entry tells the whole tale. Six
books on Sudoku, either books of puzzles or guides to solving, are already
cataloged in WorldCat. Such works should be classed at **793.73 Puzzles and puzzle
games**, under 793.7, the number for indoor games and amusements "not
characterized by action" -- a description at which some aficionados might
conceivably take umbrage? Crossword puzzles go at 793.732, and other word games
at 793.734; mathematical games and recreations are classed at 793.74. We at
Dewey Manor don't think Sudoku really counts as a mathematical game, since it
doesn't require players to carry out any mathematical operations. Sure, in most
Sudoku puzzles, the symbols that are used to fill in the grid happen to be
numerals; but variants exist, such as the *Guardian*'s Godoku, that use letters rather
than numerals, and the operations involved are logical rather than mathematical.

Logical rather than mathematical? Sounds like a line too fine for me.

--Th

Posted by: Thom | 10 August 2005 at 01:19 PM

I agree with the first post and would add that logical and mathematical recreations should class in the same place (i.e., 793.74).

I disagree with the other residents of Dewey Manor in that I think Sudoku really counts as a mathematical game, even though it doesn't require players to carry out any mathematical operations. The popular version of Sudoku (i.e., the one described in the 1st 20 Google results) is played using numbers (mathematical symbols). I think of number games as mathematical recreations, and I agree with the LC subject heading (sh85082131) which has Number games as a 450 ref. to Mathematical recreations. To my way of thinking Guardian's Godoku (which doesn't have much literary warrant) is another game: a logical game using letters that should also class in 793.74.

Lastly, it is worth noting that the Wikipedia entry for Sudoku explains the complex mathematics of the game at some length (NP-complete, etc.) and there more than a few websites dedicated to the mathematics of Sudoku; one such site explains, "People addicted to the current Sudoku craze can now log on to a UQ mathematics website to find helpful advice about solving these intriguing puzzles.

UQ Mathematics Professor Anne Street and Associate Professor Diane Donovan have created the website, http://www.maths.uq.edu.au/~dmd/puzzles-and-other.htm

What is that all about?

Posted by: LCDennis | 10 August 2005 at 06:50 PM

LCDennis's comment is timely for me, as I'm looking at 510 Mathematics in Dewey in the moment, and 511.6 Combinatorics is an area that needs a bit of work done on it.

But to me sudoku are very closely connected with Dewey, because they use properties of the number 9: 9 is a perfect square, so a 9x9 square can have 9 3x3 sub-squares inside it; and 9 is 1 less than 10, so it's the number of different non-zero digits in decimal notation. This means that it's the maximum number of subtopics in Dewey Decimal notation, without resorting to devices like topics on 0 subdivisions or subtopics in a "Other" category at 9.

Melvil Dewey somewhere referred to this limit of the decimal notationas a Procrustean bed, but I can't find the quotation: the best I can find is a reference by Henry Evelyn Bliss: "For notation classifiers have constructed their various 'decimal' classifications, which in fact are inadequate procrustean classifications with decimal notations." -- which I found in http://www.sla.org/speciallibraries/ISSN00386723V20N3.PDF (using Google, of course).

The other connection between sudoku and Dewey is the number 3: every Dewey number has at least 3 digits, and there is a decimal point after the third digit. In the printed version, digits after the decimal point are grouped in bunches of 3, too.

So that suggests a Dewey sudoku puzzle: nine 9-digit Dewey numbers arranged in the sudoku arrangement, preferably each with some sensible Dewey meaning. (No, I'm not offering a prize!)

Posted by: Giles Martin | 11 August 2005 at 11:27 AM

Oh Giles, how could you? It's bad enough having sudoko in the paper every day without you encouraging Dewey tragics to sink deeper in the mire of obsession.

Ye shall be Smited by the 200s any day now and classed at 234.47 for 236.21.

Posted by: Anne Robertson | 29 August 2005 at 12:37 AM

Indeed the wikiopedia sudoku page is very very well written, though it's not really mathematicla as theres no number calculations involved. Sudoku is purely logic it would be the same if you used letters instead of numbers.

Posted by: How To Solve Sudoku | 19 November 2009 at 03:42 PM

I've never been able to solve the Rubik's cube anyway.

Posted by: Domo Sudoku | 24 December 2009 at 08:14 AM