 There isn't a hard and fast rule. It just needs to be short enough that the ball will bounce consistently and it needs to be long enough that there's enough leaf on the plant for it to be able to survive. So it ranges from, you know, you can have a grass court tournament from anywhere from six to nine millimetres. Here at the Championships at Wimbledon, we cut all of our grass courts at eight millimetres. Again, that's because it's short enough that the players can get some good traction and good grip, but it's also long enough that the plant...