I don't know if there are a lot of Randonneuring clubs in Japan but I do know there are at least a few!
Regarding the different materials, both are chrome moly frames and both are seamed tubes. The Kaisei 022 is actually 4130 and has been around since WWII. They used to make airplanes out of the stuff and has been used to make bicycles for years. It is cheap to make and will make a bomb proof. if heavy, frame. The Tange Infinity has been around since the 80 and is probably a little lighter than the Kaisei. I doubt that you could tell the difference in the ride between the two frames. The factory may have changed materials because one is now cheaper than the other or they wanted a slightly lighter frame, but there isn't a huge difference in performance.