I'm a little confused. Uwagi are just the top garment, your shirt or jacket. It's a more general term than keikogi. The standard blue keikogi is what most of the koryu people I train with demonstrate in. At the Budosai in Kyoto every May all the koryu weapons demonstrators are in keikogi, most indigo, a few in white or undyed. The fancy clothes come out for the iai demonstrations after the koryu weapons demonstrations are finished. The blue keikogi goes back to some point at least in the Edo period when indigo was a common color for workers and cloths that would get dirty (training gear). Historically, the Aikido people who don't wear hakama wear judogi. The things being sold as "aikidogi" are very new. I could go back though my collection of Meirin Sangyo catalogs and tell you exactly when they started selling them, but it was less than 10 years ago. And most aikido people just buy judogi. Calling it an aikidogi is 98% marketing. They change a couple of seams so they have something to sell.
I was just at the Butokuden here in Kyoto this May. Koryu demonstrators were wearing a mix of garments. Some in indigo keikogi and some in kimonos.
This is kind of a fruitless argument since it's just about terminology.
In this video of early kendo practitioners
, they seem to be wearing shitagi, over half of them light-colored. I say shitagi instead of uwagi because of the way they seem to move, like pressable cotton rather than the textured, heavy style of kendogi and judogi we are used to today, which I think is based on sashiko weaving pattern.
Please note that in the Jim Breen
dictionary, if you click on the "Search using romanized Japanese" and search for "keikogi," the first example is a judo practice uniform.
WHen I say that Kano was responsible for the indigo keikogi uniform, what I mean is that I think Kano designed the white keikogi for judo, then the top half was adopted into kendo and koryu. The make of it is fundamentally similar to the keikogi top used for judo. Indigo may have been popular as a dye in the past, but it was by no means universal. Even today, you see some people wearing white keikogi tops in kendo, etc.
Also note that the indigo keikogi top does not seem to have been worn by schools of jujutsu, etc or adopted as the practice uniform for modern budo. I think it would be very strange if there were a standard practice uniform used by all the weapon arts that was not used for jujutsu (not that there was a clear distinction in the past anyhow). Likewise, if a standard training uniform existed already, why wouldn't Kano have simply created some indigo pants for it and adopted it into judo? I think the most likely explanation for both these is that causation went the other way--first Kano's white keikogi, then the adoption of his keikogi top for use by schools that traditionally wore a random collection of other normal Japanese clothes but still wanted to use hakama.
Unless I see a credible reference telling me otherwise, I am sticking with my own impressions of the situation.