Best guess from resident experts is that these were around in the (mid)1970s to early 1980s.
These pencils in particular are very nice specimens. If they were used, they were well taken care of.
Red, Blue and Green are each loaded with corresponding colored lead. Each has a stick of colored lead loaded and 2-3 more in the tube. Knock Type lead advance works on each. Very nice click feeling IMO. Erasers with jam clearing rods intact.
I bought this before I knew there were (at least) six colors so keep that in mind if you are looking for a “complete” set.
Mitsubishi Color RGB set ($49)
