“Three Chasers try and score with the Quaffle; the Keeper guards the goal posts; the Beaters keep the Bludgers away from their team,” Harry reeled off.

“Very good,” said Wood.

“Er — have the Bludgers ever killed anyone?” Harry asked, hoping he sounded offhand.

“Never at Hogwarts. We've had a couple of broken jaws but nothing worse than that. Now, the last member of the team is the Seeker. That's you. And you don't have to worry about the Quaffle or the Bludgers—”

“— unless they crack my head open.”

“Don't worry, the Weasleys are more than a match for the Bludgers — I mean, they're like a pair of human Bludgers themselves.”

Wood reached into the crate and took out the fourth and last ball. Compared with the Quaffle and the Bludgers, it was tiny, about the size of a large walnut. It was bright gold and had little fluttering silver wings.

“This,” said Wood, “is the Golden Snitch, and it's the most important ball of the lot. It's very hard to catch because it's so fast and difficult to see. It's the Seeker's job to catch it. You've got to weave in and out of the Chasers, Beaters, Bludgers, and Quaffle to get it before the other team's Seeker, because whichever Seeker catches the Snitch wins his team an extra hundred and fifty points, so they nearly always win. That's why Seekers get fouled so much. A game of Quidditch only ends when the Snitch is caught, so it can go on for ages — I think the record is three months, they had to keep bringing on substitutes so the players could get some sleep.

“Well, that's it, any questions?”

Harry shook his head. He understood what he had to do all right, it was doing it that was going to be the problem.

“We won't practice with the Snitch yet,” said Wood, carefully shutting it back inside the crate, “it's too dark, we might lose it. Let's try you out with a few of these.”

He pulled a bag of ordinary golf balls out of his pocket and a few minutes later, he and Harry were up in the air, Wood throwing the golf balls as hard as he could in every direction for Harry to catch.

Harry didn't miss a single one, and Wood was delighted. After half an hour, night had really fallen and they couldn't carry on.

“That Quidditch Cup'll have our name on it this year,” said Wood happily as they trudged back up to the castle. “I wouldn't be surprised if you turn out better than Charlie Weasley, and he could have played for England if he hadn't gone off chasing dragons.”