I take a deep breath and walk across the square. It’s Sunday evening and this is the first time I’ve been out since I went to Granddad’s this morning. In fact, I’ve not been out all weekend. All I’ve been doing is playing chess and learning new moves – the Stonewall Dutch Defence, the Chigorin Defence, the Cambridge Springs Defence. The only time I haven’t been learning is when Granddad stops to make tea and pee. He’s been in my head at school too. His voice was there in woodwork when I was chiselling a mortise joint: ‘Practise! Practise! Practise!’ It followed me to the gym: ‘Practise! Practise! Practise!’

I know, Granddad, I said to myself, now go away, but he was still chattering non-stop as I somersaulted over the horse. And in history when the British Army were landing in Normandy. ‘Practise. Practise. Practise! At every opportunity. Because your opponents will be. They will be practising before they go to bed, dreaming of chess in their beds, making their first moves as soon as they get up.’

Jake grabs my arm and we stop under our tree.

‘Come on, Felix,’ says Jake. ‘You know you want to.’

I look at our tree. It wouldn’t hurt just to go up there for an hour, would it? It was the last game today, and all me and Granddad are doing tomorrow is having a team talk. I could just talk to Jake for an hour, clean our guns and bayonets and blast a few cannonballs at the hills. I turn towards the tree.

‘Yes!’ says Jake.

‘Practise. Practise. Practise. Think that your opponents will even play on Christmas Day. Would they even think about going up a tree?’

I stop still.

‘I can’t,’ I say, moving towards my house. ‘I need to practise.’

‘Felix, you’re turning into one of them.’ Jake huffs as he walks alongside me.

‘One of who?’

‘The chess geeks.’

‘I’m not.’

‘You are.’ Jake keeps walking, then turns round and says, ‘You even put your hand up to answer a question in history.’

‘Well, I did. But only because I knew the answer for once.’

‘Ha!’ says Jake. ‘I bet it was Rebecca who told you.’

‘It wasn’t.’

‘I don’t see why you have to play chess with her every lunchtime.’ He glares at me like he does to the teacher whenever he’s sent to the Isolation Room.

‘Jake,’ I say. ‘What’s wrong?’

‘Nothing’s wrong with me,’ he says. ‘I’ve just been on my own all the time. All I want to do is go up in the tree for a few minutes and you can’t even do that.’

‘But it’s only for two more days,’ I say. ‘Then I’ll probably lose and won’t play again.’

‘Well, I hope you do lose.’ Jake walks off as I reach my gate.