Originally Posted by Velo Mule

It is called very interesting. That looks like a late 70's to perhaps early 80' bike to me, based on the crank, color, derailleur and brake levers. Cantilever brakes were not common at that time. The brakes themselves look like steel. For a bike manufacturer to go to the effort of brazing the studs for brakes in this era for a lower end bike is interesting. Then again, I believe that Japanese companies are always looking for something to give them an edge.

I am just guessing at all of this, T-Mar or someone else may know exactly that brake caliper that is and when it was produced.