He got all keen, so when we got home we had to download some chess apps for the iPads so he could keep practising and playing. He's done nothing else since!
So now every time we've been back to the playground he's been looking for challengers! The other day he played with this girl, he lost, but happily shook her hand and said 'Thank you for the game'. Good man.
Then he took on Mummy. He's got a long way to go with the thinking ahead, but it's all about keeping practicing I guess. Since he seems pretty keen on that, he might turn into a great chess player one day!