A fashion for derailleurs made up of flat steel plates swept through Japan in the early 1960’s. The 1963 SunTour Skitter and 1965 SunTour New Skitter, the 1965 DNB 66, the 1965 Sanko PF and last to the party - the 1967 Shimano Pecker. As the last entrant much of its design is derivative, the rear adjustment screws are very like the SunTour New Skitter and Sanko PF and the way the name is stamped (even the typeface) is very like a Huret Svelto.
But the Shimano Pecker has some deft touches. Despite looking like a Huret Svelto, it in fact borrows a lot from Simplex, it has two sprung pivots and the pivot of the pulley cage is off-set from the axis of the pulleys - Shimano’s ‘Servo-Pantagraph’ in embryonic form - making it the junior sibling of the Skylark. I suspect that the Shimano Pecker provided rather a good gear change when new - but I also suspect that its pivots wore and slackened pretty quickly.
I think this is a later example with a check pattern stamped onto the front knuckle, fancier branding on the parallelogram plate and no strange protector plate on the pivot which holds the cable clamp bolt.
The Pecker is the first of the famous ‘bird’ series of Shimano model names - Pecker is Woodpecker inexplicably shortened.