In Kiev 15, the shutter assembly is secured inside the diecast body like a gate dropped in front of a castle, a somewhat overkill design. The mechanism is a bit bulky, and as it's drawn here in their repair manual, it looks like the plans for heavy machinery in a cement factory. You do see intricacy in the mirror mechanism (looks like Leicaflex), and use of ball bearings around the aperture setting ring for increased sensitivity.
Not an easy Repair !