The Eastern Europeans are experts at working nymphs along and just above the river bed at close range. Although they exploit the technique on the fast-flowing rivers of central Europe, it often works well in the deeper pools of more sedately flowing streams. The essential ingredients area very heavy nymph on a dropper, which hugs the bottom, and a small imitative pattern that moves enticingly in the current about 18 in behind it. Some anglers put another small nymph on a dropper above the heavy pattern.
The angler will normally be wading right next to the fish, so unless there is a feature such as a gully the water will not be much deeper than about 3 ft. Since the nymphs are 'rolled' under the rod tip, they are sufficiently close to the angler that the fly line need not touch the water. The leader has to be long enough to allow the heavy nymph to reach the bottom of the stream, but sufficiently short for maintaining control. Typically it will be one and a half times to twice the depth of the river, which in many situations implies a leader only about 5 ft long. The margin allows for a slight angle up, down and across the current, plus any curve that the current may introduce.
A simple under-arm pendulum swing, using the weight of a very heavy fly on the dropper, deposits the nymphs far enough to be just slightly upstream of the angler by the time they reach the bottom. Once in the water, the heavy nymph 'rolls' slowly along the river bed with the current. There is no attempt to move the flies. The rod follows the leader round as the flies travel downstream, and is held at the appropriate angle (10 or 11 o'clock) to keep a slight bow in the fly line. This helps to avoid any drag, and enables the tip of the slack line, which is about 6 in above the surface, to serve as a strike indicator. Everything now relies on watching the tip of the line and striking at the slightest movement, since you are unlikely to feel anything.
When the flies have swung round it is time to raise them slowly to the surface; while intermittently holding them stationary for a few seconds. Trout may follow any of the flies as they' leave the bottom and commit themselves at some stage of the ascent. Detection of the take at this stage can come from sight or feel.