The 6139 and 6138 automatic chronographs: Seiko's entry in the 1969 race to the first automatic chronograph, and the decade of nicknamed cases that followed - Pogue, Bullhead, UFO, Kakume, Panda. The divers pass a torch down a lineage; the chronographs are a family portrait.
| REFERENCE | PRODUCED | CALIBER | CASE | RATED |
|---|---|---|---|---|
| Seiko 6139-6000/6001KEY | c. 1969–1971 | 6139 | 41 mm | 70 m |
| Seiko 6139-6002 "Pogue"KEY | c. 1971–1978 | 6139 | 41 mm | 70 m |
| Seiko 6139-6005 "True Pogue"SOUGHT | c. 1970–1977 | 6139 | 41 mm | 70 m |
| Seiko 6139-7100 "Stormtrooper" | c. 1970–1977 | 6139 | 40 mm | 70 m |
| Seiko 6138-0011 "UFO"SOUGHT | c. 1970–1979 | 6138 | 44 mm | Tachy bezel |
| Seiko 6138-0030 "Kakume"SOUGHT | c. 1972–1979 | 6138 | 43 mm | Tachy bezel |
| Seiko 6138-0040/0049 "Bullhead"SOUGHT | c. 1970–1979 | 6138 | 44 mm | Tachy bezel |
| Seiko 6138-3002 "Jumbo" | c. 1970–1978 | 6138 | 42 mm | Tachy bezel |
| Seiko 6138-802X "Panda"SOUGHT | c. 1970–1978 | 6138 | 41 mm | Tachy bezel |
| Seiko 6138-8030/8039 "Baby Kakume" | c. 1976–1979 | 6138 | 40 mm | Tachy bezel |
"c." marks a production window documented as approximate — including by Seiko's own archive.