After reading this thread, I now doubt that Congo and Osaka are the same lenses. They may come from the same plant, but the maximum f/stops are different between the two lines.
The Osaka lenses from Bromwell are definitely made by Congo. The only difference is the name on the lenses, who sells them and who provides the warranty.
Congo makes multiple designs in some focal lengths. So, that might explain any differences in max. aperture, but the 120mm Wide Angles are both f6.3 max. Also, what Bromwell sells is a subset of what Congo offers. If you look at the tables
here you will find everything Bromwell sells under the Osaka name in one of the tables.
I still have and use my little multicoated 90mm f6.3 Congo Wide Angle I bought several years ago. I actually tested five of the Congo Wide Angles, three 90s and two 120s, and kept the best of the 90s. The coverage is a bit tight on 4x5, but as long as I remember to check the corners of the ground glass for mechanical vignetting, it's not a problem.
Prior to getting the little 90mm Congo wide angle, I'd used a Linhof select 90mm Angulon as my wide angle for backpacking. The Angulon was plenty sharp (as long as I didn't push the movements), but on color transparency film it had a much cooler color cast than my modern multicoated lenses. The color rendition of the Congo was much more pleasing to my eye and a better match to my other lenses. So, I kept it and sold the Angulon and have never regretted that decision. It's so tiny that there's never an excuse not to take it wherever I go - and it's been on many long backpacking trips with me over the years and has been used to make some of my favorite images on many of those trips.
Kerry Thalmann
Really Big Cameras
