1973 Seiko Yachtman UFO chronograph ref. 6138-0010 6138-0011 6138-0017, automatic movement cal. 6138B, 40 X 44mm. case.
The 6138 is the 6139 successor, released one year later and like the 6139 were produced until 1979. The most obvious difference between the two is that the 6138 is a two register chronograph, with an added 12 hour register.
First, many call this watch the UFO, also referred to as a Yachtman Chronograph in original advertising, the series consists of models 6138-0010, 6138-0011 and 6138-0017.
The 0010 is the Speedtimer version, available in Japan, while the 0011 and 0017 were produced for the international market. I think the differences between these two are strictly cosmetic; the 0011 has a red sweep hand, lighter orange checker boarding on the sub dial, and no mention of water-resistance on the dial, whereas the 0017 has a yellow sweep, darker checkering and is marked 70m water-resistant.
Seiko mechanical watches are highly prized by collectors.
The company was founded in 1881 in Tokyo, Japan. Eleven years later, in 1892, Seiko began to produce clocks under the name Seikosha.
Seiko is a Japanese word meaning “exquisite” or success.
The first watches produced under the Seiko brand appeared in 1924. In 1969, Seiko introduced the Astron, the world’s first production quartz watch; when it was introduced, it cost the same as a medium-sized car. Seiko later went on to introduce the first quartz chronograph. In 1985, Orient and Seiko established a joint factory.
Seiko is perhaps best known for its wristwatches, all of which were at one time produced entirely in-house. This includes not only major items such as micro gears, motors, hands, crystal oscillators, batteries, sensors, LCD’s but also minor items such as the oils used in lubricating the watches and the luminous compounds used on the hands and the dials.
Seiko produces both quartz and mechanical watches of varying prices. The least expensive are around US$45 sold under the brand Alba, the most expensive, Credor Juri GBBX998, costs US$554.000.