But starting sentences with conjunctions has a few grammatical rules.

I am sure you must recall your high school English teacher telling you that starting a sentence with a conjunction was wrong. It was one of the grammar diktats that my teachers drummed into my young head. “Never start a sentence with and or but!” Those were the days, long ago, when ending a sentence with a preposition was taboo and the word whom was still in awkward, yet fashionable use.

Luckily, we now live in times that are much more flexible, and realistic. Winston Churchill put it well when alluding to obeying outdated grammar rules.

Ending a sentence with a preposition is something up with which I will not put. – Winston Churchill

Clearly, as a master in the use or the English language, it was one grammatical dictate he was reluctant to put up with.Starting a sentence with and, but or so falls into the same category. Using a conjunction to start a sentence has been around in English for over a thousand years. Well, maybe less, maybe more.But you only have to read the Bible to know that it is not a new fashion in writing.

In the beginning, God created the heaven and the earth.
And the earth was without form, and void; and darkness [was] upon the face of the deep.
And the Spirit of God moved upon the face of the waters.
And God said, Let there be light: and there was light.

So, starting a sentence with a conjunction is not wrong. Nor is it a new writing form. It is as old as the hills.

The seven coordinating conjunctions

English has only seven of these linking words. A coordinating conjunction is a word that we use to connect or join words, phrases and clauses that are related or are logical equals.

They are:

For
And
Nor
But
Or
Yet
So

They are easy to remember because they create the acronym, FANBOYS.

Understanding conjunctions

As with all aspects of English grammar, there are a couple of rules or guidelines to follow.The most important is that there are two types – subordinating conjunctions and coordinating conjunctions. It is easy to tell and remember the difference. A coordinating conjunction must be between two independent clauses. It is the most logical form.

For example:

I studied for weeks and weeks. But I failed my exam.

There was a crowd of people at the party. And guess who was there?

I lost my job last week, so I am really down. Yet I just know I’ll find a new job.

I can’t stand oysters. Nor can I eat crab.

I could go to London. Or I could go to Madrid.

However, a subordinating conjunction can come before the two clauses. It generally uses a comma before the second clause, but not always.

But because I missed the bus, I was late for work and my boss was angry.

And after I got back home, I could finally put my feet up.

But the truth is that I don’t really know.

But before the captain could answer, a major appeared from behind the guns. – William Faulkner

And even Mary could assure her family that she had no disinclination for it. – Jane Austen

Is there a comma after so?

It depends very much on the usage guides you might use. For example, Fowler’s Modern English Usage would say yes. But other guides might have a different suggestion.

For me, the word so at the beginning of a sentence is a conjunctive adverb like therefore. So, I would use a comma in both instances.

So, I missed the 5:26 pm train, and then 5:55 pm, but finally made the 6:25 pm train.

Therefore, there I was, stood up and stranded for the second time.

But for the other six conjunctions, you would not normally use a comma.

Avoiding sentence fragments

You would rarely create a sentence fragment when using a sentence with a coordinating conjunction. As long as the first phrase is closed with full stops (periods), and the second sentence starts with a logical conjunction, you will never go wrong.A fragment usually happens when you are using a subordinating conjunction.

But I got a promotion. The remedy for all my financial woes.

The problem is that the second sentence has no verb, which is then a fragment. But by adding a verb, the two phrases are now logical and correct.

But I got a promotion. It will be the remedy for all my financial woes.

If you are unsure about whether you have created a fragment, run your text through Grammarly. I find that it is very efficient at finding and highlighting sentence fragments.

But is it good writing?

Fiction writers have been using sentences starting with conjunctions for centuries. There is no reason at all not to use them.However, in formal writing such as transactional letters, there is still a reluctance to use these words at the start of sentences. In addition, the use of and, but and so, in particular, are regarded as informal register. Formal register would use furthermore or moreover for and, however for but and therefore for so.

These two groups of words clearly sound different in use, and naturally, change the formality of writing.For general modern writing such as fiction, articles or blog posts, feel free to do as you please. But all words, phrases and clauses need to be connected logically and in a way that your reader can clearly understand.

Summary

The English language is forever evolving. So, what was accepted as the rule in the middle of the last century does not necessarily hold true today.In 1960, an em dash was a rarity. Nowadays, it is a very common tool used in all forms of modern writing. For clarity and understanding, starting a sentence with but or any one of the other seven conjunctions is perfectly acceptable today.

But be sure that you understand the difference between subordinating and coordinating conjunctions and how to use them correctly. Or consult a grammar guide if you need help.And last but not least, be creative. For it is up to you as a writer to decide how best to communicate with your readers.