Oh, so you need to know what slash is, do you? Well, the short definition is "fanfiction written about romantic or sexual relationships occurring between two same-gender characters, usually male. The characters used in the fiction are denoted by X/Y, where X and Y are the characters' initials or names."
If you wish to know more details about the principles or history of slash fiction, I direct you to the comprehensive information at Slash Fan Fiction on the Net. If you are a writer who is not timid about seeing very explicit photos, you might wish to try Minotaur's Sex Tips for slash writers for useful information. If you want detailed grammar lessons and other writing advice, visit the EnglishChick's Bad Fanfic! No Biscuit!.
Now, I'll talk a little about general slash for any beginners out there, but if you want to know specifically about slash and canon, as related to H/W, you can skip ahead.
Yes, the writers of slash tales are mostly women. I think it's partly because straight females find gay males sexy, just like straight males are turned on by lesbians. But it may be more complex than that, too, because I find that women writers tend to like working out emotional and power issues in the relationship of two men that does not happen with a man and a woman. It's not just the sex that's important to us as the stories.
Now let me share with you some abbreviations that I've learned since being drawn in to slash. You can find many more abbreviations on the Glossary found in the Lessons section of the aforementioned Bad Fanfic! No Biscuit! site.
Well, those of us Holmesslash members who have had experience in other slash genres have had discussions on what constitutes a fanfic story that should be called "alternate universe," so perhaps I should include some of that wrangling here.
Now, if you've had no experience in slash (which I assume you don't since you're reading this instead of skipping onto stories, or the next section about H/W), but you have seen some more general-audience fanfiction, you might be aware that the unofficial stories of a fandom can vary in how closely they conform with facts from their fandom's canon. Sometimes, the author of a tale just makes a slight change to relatively minor facts of the canon. Sometimes the author just writes some fact that is later contradicted by the official TV canon that gets broadcast. I don't think it likely that such stories are going to be considered AU if they have such minimal canon-divergent content.
More blatantly divergent tales are those which mess with major facts of the canon. There's an X-Files tale where Mulder's sister was not kidnapped as a child, but Mulder was; Mulder's sister consequently became an FBI agent dedicated to finding out the truth behind Mulder's disappearance, while Mulder himself works as a secretive partner to Krycek, both part of the Cigarette-Smoking Man's manipulative schemes. Now that's not accidental or minor; that's willful and innovative! A tale that goes this far in redefining the canon universe is more likely to be called an AU story.
An analogous overturning of facts for the Sherlockian world might be the old (not entirely serious) proposal that Watson was actually female. "Female! What about the wives? The army?" etc. The proposal (originally made at a January 31, 1941, dinner meeting of the Baker Street Irregulars) has been laughed off by most Sherlockians, and yet some interesting, serious fiction has been inspired by that gender-switching idea.
As I said, when we Holmesslash members discussed the topic of AU stories, we differed in our definitions. Brancher's labelling of her own story as AU got challenged because the only clear change to the canon was the gender of Holmes. Jin, whose ongoing work is a novel about Watson as a woman, spoke of a "What If?" category, which she says only changes one thing about the canon, and is not in her opinion an AU.
Personally, I, as your editor, will categorise a story according to the wishes of its author. And those cases wherein I feature as the author, I go by my preference that overturning the canon in major details deserves note, whereas other matters can slide by.
Most recently, JudySue, a visitor to this humble website, offered her own thoughts on varied kinds of AU stories that exist:
In fanfic which is written while a series is still on the air (such as X-Files) AU can cover anything which departs from the series. Since the series is still ongoing the writers of canon may go in a direction that the fannish writer doesn't like or which contradicts the fanfic. For example many X-Philes continue to write Krychek with two arms (perhaps because one-armed sex is too hard to write <g>).
In fanfic that has been off the air for some time, and even for fandoms that are still airing, AU may set the familiar characters in a different time or place. The old west, on the Titanic, in the Middle Ages, etc. are very popular. There is also the popular "elf" sub-sub-genre in which one (or both) of the main characters are elves and the story may take place in the land of Faerie.
Time travel stories are also a sort of AU. Having the characters go back and meet Sherlock Holmes (and Dr. Watson) is popular in a number of fandoms. This is technically also a crossover between two fandoms (or two universes).
Another area of fanfic is based on what if a particular element of canon hadn't happened or had happened differently. For example, what if Krychek had been Mulder's original partner; what if Scully was working for the Cancerman; what if Diana was still Mulder's partner etc.
My reaction? I think maybe we should not be too concerned about precise labels and categories, and should just enjoy the intriguing variety of fiction. Hmm, mental note--I should explore what Holmes and Watson stories there are out there.
More clarification from JudySue:
Technically any story outside of the "canon" is an AU (There is a very funny story over at the Gossamer {X-Files} Archive in which Mulder and Scully show up at the fanfic archive and try and delete and destroy all stories which don't agree with canon. After much discussion about what is not acceptable it appears that nothing but canon is acceptable.) Slash in particular could be seen as an AU as the homosexuality of the characters is, arguably a long leap from canon.
I guess that way I think about it is this: Writers of fanfic draw on the text and the *subtext* of the canon when creating their stories. If the story can fit into the original canon without unduly disrupting it then it is NOT an AU.
Now, specifically related to Holmes and Watson, I thought I'd jot down some notes on some slash ideas involving the canon. Any general fan-written tale involving Holmes is usually called a pastiche (though there is a stricter definition which assumes that a pastiche would be in Watson's first person perspective, and that it would closely imitate Doyle's style). I think "slash pastiche" (or easier to pronounce "slash fiction") would be an appropriate term for a work in the slash subgenre.
Now this is a nebulous characteristic, if anything. The canon is the set of Sir Arthur Conan Doyle's original sixty Sherlock Holmes tales--4 novels and 56 short stories. Often called the "Sacred Writings" by Sherlockians, these tales are assumed to have been mostly written by Watson, with Doyle as mere a Literary Agent to Watson. The canon is like the Bible of Sherlockiana, and anyone writing any kind of pastiche ought to read the canon first. There's also a nice version of the canon with illustrations at Camden House.
However, the canon is inconsistent within itself, and is ripe for many different kinds of interpretation, as can be seen by the innumerable pastiches that exist. So I don't believe a slash pastiche would be outside the boundaries of the canon's flexibility, especially since other characters besides Holmes and Watson have been posited as being homosexual or bisexual. It's not as if homosexuality and bisexuality didn't exist back in Victorian times, after all; it was just hidden. Use your judgment for how closely you wish to stick to the canon, but realize that canonicity is seldom a hard and fast rule with pastiches.
Any Holmes/Watson pastiche is confronted with the canonical fact that Dr. Watson marries at least once, to Mary Morstan. There are proposals for other hypothetical wives, but I personally favour the "only Mary" theory.
So, how many wives did Watson have, when, and did he really love them? It's up to you. Or maybe he never married at all, and merely lied to us to cover up for his relationship with Holmes.
How shall Holmes and Watson mesh a slash relationship with their own Victorian beliefs, deal with Victorian laws against homosexual relations, or prevent themselves from being caught by Scotland Yard? This would be an optional thing to address, depending on the purpose and nature of the slash tale in question.
You might need to research the exact laws of England, and Europe in general, at the time. Enotes has a good overview of Homosexuality in Nineteenth Century Literature, and here is a reference on The History of Lesbianism. Rictor Norton's website covers Gay History and Literature, and gives some excerpts from his books. The Gayly Gay History of the World website summarizes the trends in the 1800s. Offline, there's also Graham Robb's book Strangers: Homosexual Love in the Nineteenth Century.
Keep in mind that in Victorian society, appearance was everything, and outrage at public scandals was often hypocritical compared the the silent condoning of far worse behaviour in private. People were willing to turn a blind eye to a certain extent, if their own reputations or welfare were involved. They were fruitful times indeed for blackmailers like Charles Augustus Milverton in CHAS.