Making the studio a sky.

The problem with releasing the inner child is knowing how the hell you're supposed to get them back in again. Because kids really aren't that easy to control; especially when you've spent the last 17 years pretending that you were never one in the first place.

School training started three days ago, and already I'm exhausted. My school encourages as much activity and as many games as you can possibly fit in, and - frankly - I'm not known for my athletic abilities or my physical stamina. Three days of rolling around on a carpet and pretending to be a fish - of shuffling along the floor on my stomach - and my muscles ache, my bones ache, and the little bit of my knees that used to have skin ache. And this was with a class of 7 fully grown adults, also training. We haven't even come into contact with the kids yet, so I can only imagine what will happen when there are 10 five year olds released into the room.

What's strange is that, for the first day at least, it all felt very, very strange. My body didn't feel like it was supposed to move like that; using all of my limbs (instead of just the bottom bit of my legs) to move around felt silly, and the shapes I was expected to get into felt bizarre. After years of sitting politely on chairs and walking upright, suddenly crouching into a crab shape and scuttling across the room felt ridiculous and embarrassing. Worse, the imaginary worlds that I had to play in (it's an English-through-Drama school, so the more imaginary worlds the better) felt pretty much invisible. I've learnt to create imaginary worlds sitting at my computer and using my head, but the ability to create that world and then physically play in it - to make that world real - disappeared a long time ago, and for the first day or so "let's go to the bottom of the sea!" just meant: "let's turn bright red and hope that this section is over pretty damn quickly, coz I can't see no sea, and I can't see no fish, and I definitely can't see no shark that we're all pretending to scream at."

But it came back. With a startling loud click, it all came back. Well: part of it did, anyway. I was never a particularly physical child - prone to reading books and sitting neatly and practicing my letters on sheets and sheets of green paper - so the physical element still feels a little bit strange. But playing in other worlds? Thinking like a child? Remembering what makes children laugh? Easy. And the more realistic you can make that world - the better you pretend to zip on your wings before you go flying - the more fun they have, and the more fun you have, and the more they learn. And the more they learn - I've only just realised - the more you do.

Because it's something I needed. Being an adult and walking straight and sitting neatly and exercising my brain has occupied the last twenty years of my life; in all honesty, I was chasing after adult conversation and behaviour long before I stopped being a child (when I was five I took my Godfather aside and soberly told him to "tell me grown up stuff, please"). But this is a different kind of hard work. This takes over your whole body. This isn't all about thinking; it's about doing, instinctively, and being. You can't sit down and write about an evening floating in space: you have to strap on your helmet and make the studio the sky. You have to encourage the children to stop seeing it as a classroom, and instead see it as a blank canvas that can be anything. Because the power of their heads and their bodies to make it anything is all there; they just need to tap into it.

Japanese children haven't been brought up playing these kind of games, and it's been a long time since I played them, so in a way we're starting off at roughly the same stage. But it's a stage I think I've been missing: a stage that is going to help me see the world differently. Because in opening the imaginations and the worlds of these tiny little children, I have to open mine as well. And - as a writer - that's exactly what I needed. To move away from the desk, and learn how to create a world and then actually play in it. To start using the creative part of my brain as a muscle that moves again, instead of one that just sits and stagnates in the dusty part of my brain, under the bit that works out the water bill and how much tax has been deducted from my wage slip.

It was never something I was looking for. When I came to Japan, I came for the travelling and the experience; teaching was very much secondary, and a way to make the money to stay here for a while. But I've already realised - before school has even started (I meet the kids on Monday) - that this part of the adventure is going to be as tangible and as powerful as any of the rest of it. Because this is the bit that has taken me out of my comfort zone; not walking, upright, sensibly, with other adults who just so happen to be from another country.

It's going to be hard, and it's going to be knackering, but I'm going to try as hard as I can. And if the child in the middle of me is so desperate to come out, I'm simply going to let her.