1974 SEIKO “Baby Jumbo” automatic chronograph, ref. 6139-7070, working and serviced

SEIKO automatic vintage watch, ref. 6139-7070 (known as “Baby Jumbo”) with in-house 6139B movement with EN/ES day and date feature and quickset, Japan made in 1974 (according to its serial number), case of 39.5 mm excluding the crown, automatic (self-winding with the user’s movement, mechanical, no battery!), working fine and serviced. All chrono functions work properly.

Seiko, a powerhouse in Japanese watchmaking, began its journey in 1881 when Kintaro Hattori opened a shop in Tokyo, officially adopting the “Seiko” brand name for its watches in 1924. In 1969, they launched the caliber 6139, an innovative movement widely considered one of the world’s first, if not the first, commercially available automatic chronographs. This integrated movement was produced by the Suwa factory and laid the groundwork for future automatic chronographs. Vintage Seiko watches equipped with the 6139 movement are highly sought after by collectors due to their historical significance and robust design, often featuring vibrant dials and reliable functionality.

The stainless steel case has some scratches – please check the photos. The dial color is petrol-blue. The watch also features a new stainless steel bracelet, mesh-style. It will fit wrists of up to 21 cm. Water resistance has not been tested, therefore it must be treated as NON-waterproof.
The watch will be delivered in a new padded box as seen in the photos, for a better protection during transportation and for a smart and safe storing once you receive it.

As with any other vintage mechanical watch, exact accuracy cannot be guaranteed, as it depends on many factors, including your kind of use. It has been regulated in different positions to minimize the average time gain/loss. The watch has been fully serviced in September 2025.

FREE registered (tracked) shipment worldwide. VAT is included in the price (European Union).

The uploaded pictures have maximum resolution and detail. Please study them carefully using a device with a large screen such as a computer or a tablet -cell phone screens may be too small to appreciate all details-, you can also use the zoom option, and do not hesitate to ask should you have questions. Upon receipt, if there’s any issue with the watch please let me know asap so that we find a solution. Buyers outside the European Union: please check your country’s customs policy, as the item might be subject to taxes and other fees which I cannot know and will not assume.