Ruddy Fly, Berners

Midge Flies
  onami/menami (male flow/female flow)  Japanese
  A fishing term used by professional anglers in Gujou Hachiman of Gifu Prefecture, in Japan. For onami, "o" is male, and "nami" is flow or current in English, so onami is a male flow. As for menami, "me" translates to female in English, and menami is a female flow. It seems that the meaning of the word differs a little depending on each angler.
  Mr. Yoichi Hishida called onami (male flow) the flow from the bottom of the steam towards the surface of the water, and reversely, called menami (female flow) one that flows from the surface towards the bottom. He used the term in the perpendicular dimension of the water. Amago (Japanese native trout) do not frequent onami, and only when an angler lets the bait drift into menami, he can catch fish. Because menami is the flow amago feeds in, it is also a kuinami (feeding flow, "kui" is feed).
  Mr. Toshio Onda called onami a strong center current with a choppy surface, and called menami the somewhat slower flows on both sides of the center current. It seems that Onda liked to fish onami since many anglers fish menami. Onami contains the big fish, however because the flow is fast, it is difficult to let the bait reach down to the fish deep in the current. He recommends to put the bait into samoto, that is a sucking flow besides a fall, and let the bait flow naturally (= automatically) into the depth of the center current. The bait is being put on kuinami (feeding flow) in this way.
  The words onami and menami were used in the perpendicular plane of water by Hishida, and in the horizontal plane by Onda. However, they did not mention completely different matters. The meaning of the words they used is actually different, however they indicate one common thing, that is "Put the bait on the KUINAKI (feeding flow)." Kuinami is a sucking or an in-going flow. 
  Isn't it an important suggestion for fly fishing, especially for nymph fishing? 
ReferenceAmago fishing of Gujou Hachiman professional anglers (in Japanese), 1994 (1989). Onda Toshio an fishing saint (in Japanese), 1995.
kuinami (feeding flow), hikikominami (sucking flow)
Selected Headings

Japanese Ephemella--Monkage
A spinner of Japanese Ephemera (Ephemera strigata). 
The mayfly which has finished its short life is drifted down on the water surface
in the form of a cross after the spinner fall.