This timepiece is a magnificent artifact from August 1976, as confirmed by the serial number 687071. The reference 4122-5000 is defined by its substantial stainless steel square case and a breathtaking deep forest green sunray dial that shifts from emerald to near-black as it catches the light. It is powered by the highly reliable Caliber 4122A, a precision quartz engine engineered during the height of the "Quartz Revolution" to provide uncompromising accuracy and featuring a specialized quick-set date complication at 3 o'clock.

The architecture is quintessentially 70s, utilizing a sharp, brushed stainless steel case with "hidden" lugs that create a seamless flow into the original multi-link "brick" style bracelet. The dial is a work of understated luxury, featuring hand-applied silver baton indices and the iconic "Daini Seikosha" lightning bolt logo above the 6 o'clock position, signifying its heritage from Seiko's legendary second factory. Flipping the watch over reveals the crisp caseback engraving with the reference and the serial number 687071, definitively confirming its authentic Japanese Domestic Market (JDM) heritage. This is an essential acquisition for an elite collector who appreciates bold mid-century geometry, rare colored sunburst dials, and the mechanical soul of an early precision quartz heart.