Make sure the rod is pointing out in front of you, below waist level, with the tip of the rod pointing at the water. Your wrist should be bent downward slightly. Using your forearm as a lever, lift the tip of the rod straight up to the point just past the vertical. If you were looking at yourself from the side, the rod should start at the 9:00 position and stop at the 1:00 position. Start to move the line off the water by lifting the tip of the rod. As soon as the end of the line (where it joins the leader) leaves the water, accelerate the tip of the rod to a quick stop when your thumb is level with your ear. The easiest way to pull off this speedup-and-stop motion—referred to as the “power stroke”— is to do most of it with your forearm, straightening your wrist with a snap at the moment just before the stop. Turn your head and see where the fly line goes. With proper technique, the line should form a loop as you’re moving the rod and then straighten beyond the tip of the rod, forming a line that is parallel to the ground

Most problems on the backcast come from using too much wrist and not enough forearm, and from “breaking” the wrist so that it rotates beyond a position where it is straight in line with your arm. To get a sense of this, put down your rod and point your forearm straight out in front of you, with your elbow at a comfortable position along the side of your body. Bend your wrist down slightly toward the ground. Now snap your wrist up until it is straight in line with your forearm. This is where your wrist should end on the backcast. Notice that if you break your wrist by bending it up until your thumb points up, the motion is tiring. So not only does breaking the wrist destroy a good backcast, but it also fatigues your wrist.

When you finish the backcast, the line should be bending your rod as it straightens behind you. The line will shortly fall to the ground, because you haven’t yet learned the forward cast, but during actual casting the fly line should never drop below the tip of the rod on the backcast. The rod must flex in order to transmit casting energy properly to the line, and if you bring your rod back too far by breaking your wrist, the rod will not flex enough.

You should be able to feel the rod bending as you cast. Some fly casters liken a fly rod to a spring: the energy that is built up by the fly line bending the rod is released, slinging the line out in front of you. Nonsense, others say; the fly rod must bend because it allows the tip to travel in a straight line, obtaining a greater mechanical advantage between your casting hand and the energy it imparts to the fly line.

As you practice the overhead cast, which is by far the most important cast, keep in mind that while the line travels back and forth while you cast, fly casting is really an up-and-down motion of your forearm and rod, working together as a single unit. This motion keeps the fly line pulling at an almost perpendicular angle to the rod, which puts the fly rod to its best mechanical advantage.