Diawl Bach

The Diawl Bach is one of the best stillwater flies you can have in your box, and it's about as simple as they come.

It's an old Welsh reservoir pattern, the name means "little devil," and it flat out catches trout wherever you swim it. Four materials, a few minutes at the vice, and you've got a fly that earns its place year round.

I tie mine with pheasant tail for the tail and beard instead of the usual hackle. It's stiffer and buggier in the water, and it gives the fly a bit of mottled movement as you draw it back.

The peacock herl body is the engine of the whole thing. Underwater it throws off a bronze green iridescence that nothing synthetic quite matches, and that's what pulls the takes.

Wind the copper wire on in open turns the opposite way to the herl, and it locks the herl to the shank so a trout's teeth can't strip it after a couple of fish.

Keep it skinny. This is a slim, suggestive fly that passes for a buzzer pupa, a small nymph, or a hatching midge depending on what the fish have decided to eat, and that vagueness is why it works.

Tie it too fat and you lose the profile that gets it eaten. The red thread head is a small trigger point, so don't skimp on a neat finish and a dab of varnish to bring the colour out.

Colours are up to you once you've got the basic dressing down. I like the natural peacock and pheasant, but a black herl body works well early season, and plenty of folk swim a red wire rib instead of copper.

Materials

• Hook: Partridge of Redditch light nymph, 12 to 16
• Thread: Veevus Power Thread, red
• Tail: Pheasant tail
• Body: Peacock herl
• Ribbing: Copper wire
• Beard: Pheasant tail

Fish it slow on a floating line and a long leader, either as a point fly or on the droppers as one of a team of three.

Draw it back in slow figure of eight or in inch long tweaks, and watch the line for a twitch, most of the takes come just under the surface as the fish intercept it on the swing.

If they're following but not committing, slow down even more before you speed up.