This timepiece is a flagship model from the prestigious King Seiko line, which was positioned just below Grand Seiko in terms of prestige and quality for the Japanese Domestic Market (JDM). The heart of this watch is the high-grade Seiko Caliber 5621A, a 25-jewel in-house automatic movement running at a high-frequency 28,800 bph which Seiko categorized as "Hi-Beat" to provide a signature smooth sweeping seconds hand and exceptional chronometer-grade accuracy. The case is a work of art, featuring the legendary cushion-shaped profile with sharp, flat, angular surfaces that strictly adhere to Taro Tanaka's revolutionary "Grammar of Design" philosophy, intended to make Japanese watches outshine the Swiss under any light.
What makes this reference particularly special is the "OPEN THRU GLASS" monocoque construction, a one-piece case design where the movement is accessed only through the front, significantly enhancing the watch’s structural integrity and resistance to dust and moisture. The time-only (no-date) white dial is a pure expression of mid-century minimalism, highly coveted by collectors for its perfect symmetry and aesthetic cohesion. Flipping the watch over reveals the crown jewel: the highly collectible Gold King Seiko Medallion embedded in the case back, a definitive symbol of Seiko's premium craftsmanship. With its serial number 090777, this specific unit was produced in September 1970, making it a prime specimen from the height of the mechanical competition between Seiko's internal factories.
