Rene and Paul, This is what I have found on Ritz. He wrote a book in French: Pris sur le vif, which was later translated into English: A Fly Fisher's Life. The Ritz D is his most well-known and most widely used nymph. The thorax is made of oval gold tinsel. The Ritz D should be cast upstream, dead drift, followed by an "induced take" (that's what the article says) and a wet fly swing. Should be the ticket for grayling acc to the article. Recipe: hook: 10-16 thread: brown tail: pheasant tail fibers abdomen and thorax cover: peacock fibers thorax: oval gold tinsel
HTH Martin
