The Flies: There are many woven, weighted (often beadhead) fly patterns designed specially for Czech nymphing, but your favorite local patterns will do the job just fine. Try a size 8 Pat's Rubber Legs Stonefly as the point fly and a size 14 Graphic Caddis as the dropper. Where It Works: Fish a Czech nymphing rig in classic trout runs, where fast and slow currents meet to form a seam, where there's a dropoff or depression, and behind structure like rocks. It's best to fish in runs with steady current.
How It Works:** The key here is to move the rod tip with--or even slightly lead--the line as it moves downstream (1). When it's done right, the tippet should form what's known as a Lazy J (2) as the flies drift in the current. Because you are so close to the fish, you'll have to crouch down and flip short casts. It takes practice to hone the rhythm of leading flies so they sink to the bottom but don't get stuck.