Lying

[MarieJ1987]

My 6 year has started lying, it started off with little things like so so said I was stupid, which I said you're not stupid just ignore it, which he later admitted it never happened.
Now he's turned round and said someone has hit him, which i knew straight away it wasn't true, I asked him to explain further and he admitted he was joking and no one has hit him.
I've explained why lying isn't good and that he must tell the truth and not make things up.
Is this common at his age? Is this a phase? What do I do now?

Lying is common and a good sign, it's means he can understand that different people know different things.
The problem is actually the judgement, you are saying isn't good but actually lying is the learning phase of understanding other people's perspectives how they differ. Yes like everything the learning phase is a bit extreme, but he will get the hang, and if you can try to lean into it a bit it would help him.
Once you think about it you realise adults use this essential skill all the time, even if we don't consider it out and out lying.
Good luck and hope it goes well.