It is lst (low stress training). You can tie down your top to create multiple tops, spread your branches out more for better light penetration, and I'm sure people use it in other ways. I'm a first timer and tied down the top on a big plant I had, and I must say it was by far the best idea I had. The light penetration is waaaay better, and now I have a nice even canopy of tops from one plant. You can check it out in my signature link if you like. Think the most recent pics are on page 5