BrookieBoy,
Gogi, a subspecies of Iwana, also lives in the area where I live. I haven't been fishing for Gogi yet this year, but I'm planning to enjoy it with my friends. Hiroshima, where I live, is located relatively south of Japan, so we need to reach a high mountain stream to fish Gogi. Iwana, including Gogi, are said to be less selective for flies. I mainly use form flies around #10 because I enjoy Gogi fishing during early summer to summer when telestrial patterns are effective. In Hiroshima, Gogi, like Brook trout, is often cryptic and secretive. On the other hand, in areas located in the north of Japan, such as Hokkaido and the Tohoku region, Iwana and subspecies of Iwana are common, so they are not so important, and Yamame are more important.
The URL of the Gogi Fishing reports that I have posted on this forum are shown below.
https://fiberglassflyrodders.com/forum/viewtopic.php?f=2&t=70230https://fiberglassflyrodders.com/forum/viewtopic.php?f=2&t=72336https://fiberglassflyrodders.com/forum/viewtopic.php?f=2&t=72475