Aparently, there's a "rule" that you shouldn't start a sentence with however, which is as clearly nonsense as the one which says you shouldn't start a sentence with but. As I was unpicking in the context of that bizarre stuff that gets peddled about not using was, this is typical of the rubbish that gets spouted by those who teach rules not by what's actually going on, but by spotting "signals" which are a possible symptom of something not-right, not the cause of it. For a start, there are plenty of times when starting a sentence with 'however' is entirely, formally correct.
However conscientiously you keep them, rules shouldn't be rules but tools, or possibly guidelines.
However, that doesn't mean you don't have to know what those tools/guidelines are.
are both wholly correct by any grammatical measure you care to apply - and I'd argue that the title of this post is, too. Next comes the one the rule-bound get antsy about, with a little more reason:
I want to go to the fair. However long it takes me to get there. I shall ride the helter-skelter as soon as I arrive.
There are two reasons for suggesting that this sentence should be re-cast. One is to do with the fact that However long it takes me to get there is not a complete sentence, in the grammatical sense. Minus one mark in the English Language exam. There's no main verb phrase ("finite verb" in old money) to make it a unit of action, and so that assemblage of words can't stand on its own. The however phrase, by definition, relates to something, but it isn't connected up by a comma up to one or other of those two units of action, and divided from the other by a full stop. It isn't, if you like, a unit of sense.
Because of this, comes the second reason. "Breaking the rule" - which I'd rather call the convention - about complete sentences has actually blurred the meaning, and so the meaning that the writer is trying for isn't actually conveyed to the reader. The version above could mean
I want to go to the fair, however long it takes me to get there. I shall ride the helter-skelter as soon as I arrive. Or, in other words:
However long it takes me to get there, I want to go to the fair. I shall ride the helter-skelter as soon as I arrive.
but it could just as well mean
I want to go to the fair. However long it took me to get there, I shall ride the helter-skelter as soon as I arrive. Or, in other words:
I want to go to the fair. I shall ride the helter-skelter as soon as I arrive, however long it took me to get there.
Which did you read it as? Notice that in the second pair I've changed takes to took to make the point: in this pair, the qualification "however long" is being made not as part of "I want to go", but looking back on the journey, from the top of the helter-skelter, clutching your doormat.
So the fundamental mistake isn't "starting a sentence with however", it's about working or failing to work with the conventions of grammar and syntax to convey meaning as exactly as possible. But it takes time to explain and understand (and write in the margin of my students' work), as anyone who follows the Itch will know. Which, I suppose, is why "rules of thumb" like "don't start with however" (or even the horrid "show don't tell") grow up: it's easier to make a rule out of something which is actually only a symptom, than to explain the pathology of the disease. But not explaining - not trying to understand - what's really going on it's like saying "When the canary stops singing you evacuate the mine" and no more: some people just install a blackbird instead despite the fact that they're not nearly as good at the job. And some people will extend that idea to the canaries who live - and sing - in the weaving loft and the pub and their granny's kitchen, and evacuate all three at the first silence.
But, of course, in creative writing we're not only interested in accurate meaning, we're interested in expressiveness: we're trying to convey how language is said and felt, as well as written. Even in narrative, creative writing (fiction or non-fiction) takes on varying amounts of the human voice, expressive ungrammaticalnesses and all. So in another sentence, setting that however phrase off on its own might be just what you're trying to do, to give the declaration of "however long" maximum impact.
I don't care what he says. However he says it. I'm not going.
And any creative writing teacher who slaps your wrist for writing that in an appropriate context and voice deserves to be hung, drawn and quartered. I'll come and applaud. But you still won't get me to say that "you can't break the rules till you know them", because they're not rules, they're conventions. And I mean conventions in a positive sense: it's not nature's law that we thank people for presents, but it's grown up to become a "rule" as part of being a social species. Nor is it a rule of nature or government to wear black at funerals, it's a convention which carries certain meanings - sadness, respect, community, self-restraint perhaps, self-effacement - and if you want to express those things to and about the dead person (in Europe, at least) then you follow it. It's one of those things that we all know - that we explain to our children, for example - because if we don't, we'll be misread. Sometimes, the dead person or the family say they don't want black worn because they want the occasion to be about celebration, not mourning: bright colours, please. But would the effect be so joyful if it wasn't, in some way, a surprise to see the coffin followed by a stream of scarlet and turquoise and orange? Put another way: punk wouldn't be rebellious and counter-cultural - would lose a large part of both meaning and expressive effect - if normal office wear for your average capitalist pig was a pink mohican and safety pins through the nose.
Similarly, an incomplete sentence which starts with however will only gain that extra force if it's not normally used like that. And it's very important to realise that deliberately bending a convention to your expressive purposes won't achieve your purpose if you don't understand how however - say - works. As I was talking about further up, the chances are that you'll mis-use it in a way which actually blurs the meaning, rather than strengthening the expression.
My favourite book for people who want to use grammar conventions expressively, as tools, is David Crystal's follow-up and companion volume to his Rediscover Grammar. In that, he discusses conventional usage very clearly and well. In Making Sense of Grammar he discusses how those conventions can be kept, or broken, to your best expressive purpose. It lives on my desk.