Bloody hell, it’s happened again.  I’ve got a perfectly sound use of which in a defining relative clause and someone’s objected to it. A while back I had ten in a draft and a German colleague went through changing them all to ‘that.’

Yawn. Here we go again: When do we use which and when do we use that?

As any standard grammar will tell us:

Non-Defining clauses MUST use a comma followed by which.   Defining clauses can use either that or which and have no comma.  

In defining clauses (ones which ‘define’ or give essential information to identify the noun they follow), the author can choose ‘which/that’ to suit the cadence or the repeating patterns in the work.


  1. The garden which we walked through had been trampled by Microsoft grammarians.
  2. The garden that we walked through had been trampled by Microsoft grammarians.
  3. My own private garden, which we walked through yesterday, had been trampled by Microsoft grammarians.

These are all good sentences.

The first two are defining. The clause following that/which is necessary to define the garden we’re talking about.

The third sentence is not defining the garden as it’s already clear which garden we’re talking about.

You cannot use ‘that’ in a non-defining clause – a rule of thumb is that you cannot use it after a comma. So

  • My own private garden, that we walked through yesterday, had been trampled. 

would be wrong.

With examples 1 and 2, because we have a new subject, there’s also the choice to miss out the that/which altogether.

  • The garden we walked through had been trampled….

Here’s an example with no new subject for the clause. We can choose ‘that’ or ‘which’ but we can’t miss them out:

  • The grammar which is being changed has only been changed because of soulless corporate practices.
  • The grammar that is being changed has only been changed because of soulless corporate practices.

You can play with these. And that can be contracted to that’s, which could be preferable for a more colloquial feel. To native speakers there’s an increased formality around ‘which’, perhaps, but IT”S NOT WRONG!

Why have Microsoft become the arbitrators of English language?

Language does change and that’s wonderful and evolutionary and makes us all feel like the soup of society is running down our faces and into a gutter where it can be spooned back over our heads. Great. The change which is happening in this case though, is one that comes only with a corporate convenience and the kind of change that comes through slavery to American grammar-checks.

How many more?  Is there a project to ascertain how word-processing devices are changing language and what the driving force is for that change?  With the that/which conundrum it seems simply to be a cosier algorithm for the grammar check programmers – only allow the word ‘which’ when there’s a comma before it. Always use ‘that’ when there’s no comma.

This isn’t simply a force of American English, the ‘that’ form is arguably more firmly embedded across the US, but grammar codes are not specifically trans-Atlantic on this one – in any case American English tends to hold more aged conventions for longer, as they do with ‘whom’, which in British English can seem fussy.

This is more particularly a Microsoft thing.

Our flow of creative choice has been stifled. More worryingly we don’t recognise it. Increasingly, the word ‘which’ simply looks wrong because it’s being expunged by word processing checks. We don’t trust ourselves, we just change to the MS patterns. We grow to trust and love our built-in grammar authority. Foreign schools with non-native speakers are looking for easy rules to give their students. It’s easier to give a rule than explain a quirk or offer a choice. Easier to mark. Easier to tick the box and move on.

Time to stand up for ‘which’ if you like it.  Or sell your soul to the company which gave you Comic Sans and Calibri fonts as the default look and feel of our world of words.