Kirk and Tim were fishing on the Colorado River by Glenwood Springs in September. They made a $20 bet on who would catch more fish, using only one fly. It was a typical early fall Colorado day ... in the 30s in the morning; up to the mid 60s by midday. It was breezy, partly cloudy, and the water was pretty clear, but not terribly low. Both anglers were using 5-weight rods, with 4X leaders, and 4X tippets. They agreed to adjust weight, use strike indicators, whatever ... but they had to stick with the same fly pattern. At day's end, as Kirk snatched the Andrew Jackson bill from Tim (having caught 20 more fish that day), he spilled the beans and showed his friend the "secret pattern." Tim couldn't believe it ... here he had been fishing a Prince nymph all day (not a bad call for all-around conditions), but Kirk was using one of the oldest tricks in the flyfishing book. What was it, and why did it work?