I think this is a fairly early Taiwanese derivative of the Shimano Skylark. It has the cable clamp mounted on the front knuckle (rather than the outer parallelogram plate), it has springs on the adjustment screws to prevent loosening (rather than the later plastic piece) and it is branded with large embossed letters. These are features of the Shimano Skylark from 1974, and they had all disappeared from the Skylark by 1981.
Interestingly the design of the cable clamp arrangement is ‘borrowed’ from SunTour rather than from Shimano.
This example is a short cage ‘SS’ version, with a built-on hanger plate.