Ron, the Fujichrome trade name was used for Fuji's E4 films, and the Velvia name was not used for Fuji's first E6 films.
I've never come across a Fuji colour reversal film that was not processed in E3/E4 or E6 chemistry. The only reference I've ever seen to a Kodachrome type process was the early Ilford Slide film in the 1960's.
Ian
In 1959 and 1960, I purchased Fujichrome and Sakura Color film in Japan and other far east countries. They were Kodachrome work alikes in that generation. I was a guest at the Sakura Color processing plant to see it, and also at To E studios to see the set for the latest Godzilla epic on the roof of the building. They used Fujichrome and Technicolor for MoPic and Sakura unmasked color neg for stills. I have lots of shots on all of these except for the motion picture. I was charged with buying it for the AF for 'special projects'.
In fact, we used only Kodak color (E2 and E3) at that time, because we had no way to process the Japanese reversal film.
When Kodak transitioned to E6, there was still a Kodachrome like film in the far east made by both companies, but it was rapidly waning. It effectively vanished, but there was a short hiatus until Fuji was able to make an E6 compatible film.
I remember it to be Velvia, but of course I may be wrong. In the event, the film would not go through the E6 process properly and there were headline articles on it in major US magazines.
At the same time they introduced it, they placed ads "From the people who brought you Pearl Harbor", and this was so poorly recieved by the US audience there was a huge outcry. The ad was condemned by major news stories and Fuji withdrew the ads. It was replaced by the ad showing two eyes with the statement "These eyes can see color no one else can see and they designed the new Fujichrome films" (that is a paraphrase of the actual title to the picture.
From that time forward, Fuji reversal films rapidly improved.
Now, the market varies from Japan to the US to England and Europe, so this story of mine may be somewhat cross threaded due to your perspective and mine, as I was travelling over 1/2 of the globe during part of that period as noted above.
PE