Seiko 62MAS 6217-8001

The Seiko Reference 6217-8001, affectionately known as the “Big Crown” 62MAS, was produced for a relatively short period, primarily between January 1966 and June/October 1967. It succeeded the very short-lived 6217-8000 “Small Crown” (produced April-June 1965 ), incorporating key improvements for Seiko’s first professional dive watch series. The most significant feature distinguishing the 6217-8001 is its larger, easier-to-grip winding crown, a modification that required changes to the case and crown tube design for better usability and likely enhanced water resistance integrity. Housed in a 37mm stainless steel case with a distinctive cushion shape and short lugs , the watch features a 150-meter water resistance rating , a bidirectional rotating bezel with a 60-minute scale , and a prominent domed acrylic crystal. The dial is typically a dark grey sunburst with large, luminous rectangular markers and a date window at 3 o’clock. Inside beats the Seiko Caliber 6217A, a 17-jewel automatic movement operating at 18,000 bph, featuring a quickset date but lacking hacking or manual winding capabilities. The significance of the 6217-8001 lies in its status as Seiko’s (and Japan’s) first professional dive watch , establishing a design language and technical foundation that influenced decades of subsequent Seiko divers. Its reliability was proven through use by the Japanese Antarctic Research Expedition (JARE) , and its iconic design continues to be celebrated through modern Seiko reissues.  

Specifications Table

Variations and Key Features

The Seiko 6217-8001 “Big Crown” 62MAS, while having a relatively short production run itself (Jan 1966 – mid/late 1967 ), exhibits key features and variations that distinguish it and are important for collectors.  

Case:

• Material: Stainless steel.  
• Shape: Distinctive cushion-like shape with short, squared-off lugs.  
• Dimensions: ~37-38mm diameter, ~46mm lug-to-lug, 19mm lug width.  
• Crown: The defining feature is the larger, signed “Big Crown” at 3 o’clock, designed for better grip. It’s a push-pull type, not screw-down.  
• Case Tube: Modified case design compared to the 6217-8000, featuring a longer crown tube with a flange and a recessed case side to accommodate the larger crown.  
• Case Back: Features engraved markings. Two main types appeared on the 6217-8001:
  • Dolphin Case Back: Used from Jan 1966 to Jun/Oct 1967. Includes two sub-variations (Gen 2 with long rostrum, Jan ’66-Jan ’67; Gen 3 with short rostrum/round flippers, Feb ’67-Jun/Oct ’67).  
  • Horseshoe Case Back: Introduced around March 1967 and produced concurrently with the Gen 3 Dolphin back until the end of production. Became a standard Seiko design later.  
• Daini Production: A specific run produced by the Daini factory in Spring 1967 features unique movement/case back engravings and exclusively uses the horseshoe case back.  

Bezel:

• Type: Bidirectional rotating external bezel.  
• Insert: Black aluminum insert with a 60-minute scale and a luminous pip at 12.  
• Edge: Coin-edged for grip; variations in the height/depth of the ridging exist but are not strictly tied to the 8001 reference.  

Dial:

• Color/Finish: Dark grey with a sunburst finish, often appearing near-black.  
• Markers: Large, applied rectangular hour markers, filled with lume. Seiko used an embossing technique for durability.  
• Date: Framed date window at 3 o’clock.  
• Text: Typically includes “Seiko,” “Automatic,” and potentially water resistance/jewel count details.  

Hands:

• Style: Broad, lume-filled baton hour and minute hands.  
• Seconds Hand: Sweep seconds hand with a characteristic rectangular lume plot near the tip.  

Crystal:

• Type: Domed acrylic (Plexiglass).  

Movement (Caliber 6217A):

• Type: 17-jewel automatic (self-winding).  
• Frequency: 18,000 bph (2.5 Hz).  
• Features: Quickset date. Non-hacking. Non-manual winding.  
• Origin: Derived from the movement used in Seiko’s 1964 World Timer GMT watch.  

Additional Information

The Seiko 6217-8001 “Big Crown” 62MAS is a landmark watch, representing Seiko’s successful entry into the professional dive watch market and establishing a design legacy that continues to this day. Its selection for the 8th Japanese Antarctic Research Expedition (JARE) provided crucial real-world validation of its robustness.  

For collectors, the 62MAS (both 8000 and 8001 references) is highly desirable. The 6217-8001, while produced in larger numbers than the ultra-rare 6217-8000 “Small Crown,” is still relatively scarce, especially in excellent, original condition. Key factors for collectors include the condition of the case (sharp lines), dial and hands (original lume patina), bezel insert, and the specific case back variant (Dolphin vs. Horseshoe) which helps in dating.  

The market value of the 62MAS has risen significantly, driven by its historical importance and the frequent modern reinterpretations released by Seiko, which continually reinforce its iconic status. These modern homages, while popular, also highlight the unique charm and historical significance of the original vintage models.