Talk:Sudoku

"The Japanese Embassy to some country nominated the song to receive some kind of award from someone"

This is, actually, a reasonable summary of the source. It's an Australian newspaper taking about a British singer, and just says, "The Japanese Embassy has also nominated [the song] for an award," which is very vague. But the phrasing is weird and could surely be improved? TRiG (talk) 18:41, 21 March 2025 (UTC)

It appears that I am who introduced that phrase into the article, and I stand by it, although it might be better to just remove the sentence describing the nomination. If a nomination for an award is notable, there should be a clear identification of what the name of the award is and what person or organization bestows the award and exactly who made the nomination. If we can't identify such basic facts, then we should not gloss over the situation. A "World's Greatest Dad" award may be notable if it is bestowed by the International Association of Parental Leadership, but is probably not notable if it is given you you by your son and consists of a certificate drawn with crayon on a piece of scrap paper. —⁠ ⁠BarrelProof (talk) 10:57, 14 July 2026 (UTC)

Proposal to add external link: PlaySudoku.com (accessible Sudoku trainer)

I propose adding the following entry to the External links section: https://www.playsudoku.com/en — An accessibility‑focused Sudoku trainer and analyzer (WCAG 2.2 AA), with keyboard navigation, screen‑reader labels, candidate notation, and interactive hints that explain common solving techniques. Rationale (per WP:EL) Unique, substantive resource (WP:ELYES): The site is not simply “another place to play.” It provides structured, interactive guidance (candidate marking, technique‑driven hints) and is designed to be fully operable by keyboard and screen readers (WCAG 2.2 AA), which is uncommon among general Sudoku sites. This directly complements encyclopedic understanding of Sudoku solving methods and accessibility considerations. Non‑duplicative and minimal: This would be a single, targeted link; I am not proposing a list of similar play sites (WP:ELMIN). Non‑promotional: The description above is factual and avoids calls to action (WP:NOTPROMO). If editors prefer different wording, I’m happy to adjust or withdraw. If consensus is against inclusion (e.g., if editors feel this falls under WP:ELNO as one of many play sites), I’ll defer to that outcome. Thanks in advance for reviewing. Stefano.chermaz1 (talk) 19:28, 17 August 2025 (UTC)

No, we're not going to link to any sites for playing Sudoku. There is no reason we'd made an exception for your site other the many, many similiar ones available. MrOllie (talk) 19:44, 17 August 2025 (UTC)

Merge from Strimko

Strimko example from the Dutch Wikipedia article

It seems to me that Strimko should be merged into this article — being (AFAICT) exactly a synonym for "Jigsaw Sudoku," it deserves just a sentence or two under § Variations of grid sizes or region shapes. I'm unlikely to try to do that merge myself, though. --Quuxplusone (talk) 15:44, 10 February 2026 (UTC)

...of course as soon as I post that, I see there's a better nl:Strimko article on Dutch Wikipedia! It includes a better example image than the one I whipped up yesterday: namely it shows that in a Strimko the regions not only can be rounded polyominoes, but in fact the regions can cross each other! So Strimko is yet a little more generalized than "Jigsaw Sudoku" as I (poorly) understand the term. Should still be merged, but deserves slightly more than to be characterized as "exactly a synonym." --Quuxplusone (talk) 15:51, 10 February 2026 (UTC)

Quuxplusone, this has gone unopposed and you should be good to carry out a merge. Thebiguglyalien (talk) 01:04, 17 March 2026 (UTC)

I've removed the merge tags since this is inactive, anyone can carry out a merge if they wish. Thebiguglyalien (talk) 23:55, 15 April 2026 (UTC)

Capitalization?

This article currently has inconsistencies of capitalization between "Sudoku" and "sudoku" (see especially the section "Killer sudoku" [sic]. The same inconsistencies are present in Mathematics of Sudoku, Sudoku code, and Killer sudoku, at least. I have seen both versions on other sites as well. I don't feel strongly about which capitalization we should use (although I did use lowercase in a recent academic paper) but I do feel that we should use a consistent case, so what are the opinions of others here on which to use? Note also that if we are to treat it as a capitalized proper name or trademark (as I believe it is in Japan but not elsewhere), MOS:ITALICTITLE might suggest that it should be italicized, which we are not doing, whereas if we treat it as not a proper name, but merely a word for a classical game, then MOS:NEITHER would suggest that it should not be italicized. (See a related discussion at Talk:Square on the italicization of Scrabble, from which this question branched off. See also a really old discussion at Talk:Sudoku/Archive 1#Italics.) —David Eppstein (talk) 05:57, 22 September 2026 (UTC)

A brief search does seem to indicate that sources (including newspapers, academic papers, books, ...) are mixed in their capitalization of sudoku/Sudoku. Italics seem rare, but I can find a few examples. My personal vague impression (not based on any kind of expertise or extensive data gathering) is that sudoku is a pretty genericized name, and doesn't seem to have any kind of trademark enforcement, at least where people are writing in English. I'd go for lowercase, but don't feel strongly about it. –jacobolus (t) 06:20, 22 September 2026 (UTC)

MOS:GAMECAPS says: "Sports, games, and other activities that are not trademarked or copyrighted are not capitalized (except where one contains a proper name or acronym, or begins a sentence)," while "Trademarked sports and games are capitalized like any other trademarks." According to the Sudoku article, there is some kind of trademark in Japan, but it is not clear to me whether that trademark applies to the Latin-character term by itself or only when accompanied by Japanese characters in a particular pictographic layout. It looks like it was granted or applied for in 2006 or 2007. Was the term already in widespread use before then? The game itself dates back to 1979 (1984 in Japan), before the name was established. —⁠ ⁠BarrelProof (talk) 18:35, 22 September 2026 (UTC)

Re pre-2006 use of the name: see Kanamoto, N. (2001). A Well-Made Sudoku is a Pleasure to Solve. Nikoli. —David Eppstein (talk) 19:09, 22 September 2026 (UTC)

I also found several trademarks in the U.S., such as this one, which was just registered last year, and this cancelled one and this one. I think each of them is for a particular logo and font styling, not just any use of the term. Thus, I believe that sentence in the Sudoku article is basically wrong or at least grossly misleading. I think it is basically not a trademarked term. Anyone can use it, and it should be lowercased. —⁠ ⁠BarrelProof (talk) 19:32, 22 September 2026 (UTC)

A 2007 BBC article says sudoku was introduced to Japan by Maki Kaji, president of Nikoli, who had encountered the puzzle in the United States. It does not use the word "trademark". It says "It is a few years since he first published Sudoku, a game he had come across in the United States. He gave it its name and helped to make it the worldwide success it is today. ... He said he did not make a lot of money out of Sudoku because he did not copyright the puzzle. But he says that helped its success, because it meant others could pick up the idea and publish it more widely. He now owns the copyright for the puzzle in Japan and still publishes new collections of the puzzles." I am not a Japanese copyright lawyer (or any kind of lawyer), but my impression is that this is using the word "copyright" incorrectly, and maybe it's referring to a trademark rather than a copyright. I also suspect the writer did not understand some basic concepts of copyright and trademark, but it sounds like it is saying that the term had no trademark when it was introduced in Japan. As far as I know, it is not possible to copyright the general concept of a puzzle like this one (although it might be possible to copyright a particular puzzle collection, so others cannot just publish a copy of an entire book of puzzles). Nikoli later registered a trademark (filed November 6, 2006, registered June 22, 2007), but I think that is only for a particular logo and styling, so I would be surprised if that gives Nikoli the exclusive right to use the term "sudoku" in Japan. Another cited source explicitly says that Nikoli "trademarked the name", but I don't know how reliable that source is. (It also confirms that "In April 1984, Japan's puzzle group Nikoli discovered Dell's Number Place [and] presented it for a Japanese audience in the pages of puzzle paper Monthly Nikolist.", which confirms that it had come directly from the U.S. to (someone at) Nikoli, although I'm surprised that this source seems to have a grammar error, and I note that it refers to "puzzle group Nikoli" rather than Kaji personally.) My impression is that sometimes, trademark/copyright owners try to give people the impression that they have broader rights than they actually have (consider, for example, The Smiley Company and Happy Birthday to You). —⁠ ⁠BarrelProof (talk) 18:32, 24 September 2026 (UTC)

Nikoli does seem to claim to hold a trademark on the term itself, per this and this, although some sources seem to hint that the term wasn't originally trademarked, and the scope of the trademark seems to be limited to Japan. Without knowing more, I still don't have a firm opinion about whether the term should be capitalized on Wikipedia. —⁠ ⁠BarrelProof (talk) 18:09, 25 September 2026 (UTC)

Among the sources cited in the Wikipedia article, the Time Magazine and New York Times sources use lowercase. Most of the others appear to capitalize it (at least most of the time – I spotted one that was not internally consistent). —⁠ ⁠BarrelProof (talk) 17:09, 26 September 2026 (UTC)

When adding a citation to Psychology Today today, I noticed it also uses lowercase. (That is not why I added a citation to it in the article.) —⁠ ⁠BarrelProof (talk) 05:04, 27 September 2026 (UTC)

Is there any apparent trend in dates in the casing? My guess would have been more recent = more likely to be lower case, but none of those three lowercase sources is recent. —David Eppstein (talk) 05:21, 27 September 2026 (UTC)

All three of those lowercse sources were written within a year of each other (May 2006 – March 2007), and I noticed something else that they have in common, which is Will Shortz. Shortz is the "puzzlemaster" of The New York Times. He is also the author of the Time Magazine article and is also prominently featured in the Psychology Today article. The New York Times is a very well-reputed source, and it tends to use lowercase more than lesser publications do. —⁠ ⁠BarrelProof (talk) 05:58, 27 September 2026 (UTC)

As a footnote, I don't think it should be in italics. It is not the title of a specific board game, video game, or trading card game (the cases discussed in MOS:ITALICTITLE). —⁠ ⁠BarrelProof (talk) 17:22, 27 September 2026 (UTC)

Per MOS:CAPS: "only words and phrases that are consistently capitalized in a substantial majority of independent, reliable sources are capitalized in Wikipedia". Sudokuo isn't consistently capitalized in sources so we shouldn't capitalize it either. Popcornfud (talk) 05:25, 30 September 2026 (UTC)

Reading the history in the article, it does not meet Wikipedia's standard for capitalization. It is a traditional game published under a variety of names and the name sudoku was later applied to it. There is some copyright of something in Japan, but it does not appear to be for the English word. Capitalisation is mixed in sources. Neither of Wikipedia's standards are met for capitalization. It is not a proper noun and it is not capitalized in "a substantial majority" of sources. SchreiberBike | ⌨  12:50, 30 September 2026 (UTC)