Here is the fly pattern sheet for the Green Drake Klinkhåmer Variant, a variant of the original Klinkhåmer Special.
Daiichi 1160, #10 – 16
8/0 Uni Olive Dun for body, 16/0 Veevus Olive for hackle
Superfine Gray/Olive or Caddis Green
Peacock herl, 3 strands
Here is the history of the Klinkhåmer Special from Hans van Klinken in his own words posted on the website by Tom Sutcliffe called – The Spirit of Fly Fishing – in April 2012, the 25th anniversary. CLICK HERE
Note: The fly is designed so only the hackle will float the fly with the body and thorax submerged. Use at least 5 turns of hackle for smaller flies and 7 or 8 turns for larger flies. Keep the long post to help you see the fly.