The OP asks about Japan, not Singapore. In that case the "ROLLEINAR" [35mm] and "ROLLEIGON" [6x6cm] brand of lenses were made in Japan. (Not to be confused with the German-made close-up lens of the same name.)
All of the TLR's are made in Germany. The little Rollei 35's are mostly made in Singapore, but originally in Germany. I have several SL35's, which are branded Rolleiflex, and one is made in Germany, the others in Singapore.
Many of the lenses that fitted the later Rollei 35mm SLR's were made in Japan by Mamiya, but used Voigtlander names as Rollei and Voigtlander had joined forces by then.
I think the Seiko shutter of the GX was made in Japan. The SL66 was never made in Singapur, but some SLX were.
The SLR was called Rolleiflex.
See here: https://www.google.gr/search?q=rolle...w=1600&bih=883
I have never known what the connection between Rolleiflex and Honeywell was. Some of the prisms say Honeywell... which is USA I think. (?)
Honeywell was a US importer for overseas cameras. Some imported models were marketed under the Honeywell brand.
But that was not a one-way-street. The electronics campany not only imported cameras but also handed out own design, such as for a electronic flashlight that was manufactured and marketed by Rollei.
I have two Rollei 35s. One is an original 1966 model from Germany. The other is a Singapore model. I think that some of the early postwar Rolleiflex cameras had bodies made in West Germany and lenses from East Germany.
The mercury-switched thermostat on my wall was made by Honeywell in the US, probably 1960s.
My 2.8F is mid 1970s "Honeywell" era; it reads "Honeywell" on the flip-up finder. Of course that camera and its lenses were made in Germany.