Description
SEIKO 5 Sports Field GMT Street Style SBSC013 Automatic Men’s Watch
The SEIKO 5 Sports SBSC013 gives the Field Series GMT design a monochromatic street-style treatment. Its matte-black dial, black hard-coated stainless steel case and black cow-leather pass-through strap create a unified appearance, while a prominent red GMT hand provides a clear visual accent.
This Japanese-market model is powered by SEIKO’s mechanical Caliber 4R34, combining automatic winding, manual winding and a 24-hour dual-time display. Its compact 39.4 mm case makes it suitable for everyday wear without sacrificing the robust visual character associated with the SEIKO 5 Sports collection.
Matte-Black Field GMT Design
The dial follows a field-watch layout with large Arabic hour numerals, a clearly defined minute track and broad central hands. The matte finish minimizes unnecessary reflections and complements the black treatment used across the case, bezel and strap.
A five-sided red GMT hand stands out against the black dial. It completes one rotation every 24 hours and is read against the fixed 24-hour bezel, allowing the wearer to display a second time zone alongside the primary local time.
The red GMT hand is coordinated with additional warm-colored dial details, creating visual separation without compromising the watch’s predominantly black appearance. A framed date window at 3 o’clock adds everyday calendar functionality.
Mechanical GMT Caliber 4R34
The SBSC013 is powered by SEIKO’s Caliber 4R34, a mechanical automatic movement that can also be wound manually through the crown. Normal wrist movement winds the mainspring during wear, while manual winding allows the watch to be restarted or given additional power when necessary.
Caliber 4R34 operates at 21,600 vibrations per hour, equivalent to six beats per second, and contains 24 jewels. When fully wound, it provides an approximate power reserve of 41 hours.
SEIKO specifies an accuracy range of +45 to −35 seconds per day when worn on the wrist within a temperature range of 5°C to 35°C. The actual daily rate of a mechanical watch may vary according to temperature, position, activity and the remaining mainspring power.
The movement includes a 24-hour hand for dual-time display, a date calendar and a stop-seconds function for more precise time setting.
Black Hard-Coated Stainless Steel Case
The stainless steel case is finished with a black hard coating that supports the SBSC013’s understated street-style appearance. It measures 39.4 mm in diameter, 47.9 mm from lug to lug and 13.6 mm thick.
These proportions are shared with the bracelet-equipped Field GMT models, but the lighter leather strap reduces the completed weight to approximately 79 g. The result is a mechanical GMT watch with a substantial visual presence that remains comparatively light on the wrist.
A thick, curved Hardlex crystal rises above the bezel and adds depth to the profile. The fixed black bezel carries the 24-hour scale used with the red GMT hand.
Black Cow-Leather Pass-Through Strap
The SBSC013 uses a black cow-leather pass-through strap rather than the stainless steel multi-link bracelet fitted to SBSC011. This one-piece configuration passes underneath the case, reinforcing the watch’s field-inspired appearance and creating a continuous black surface beneath the watch head.
The strap has a 20 mm attachment width and accommodates a wrist circumference of up to approximately 225 mm. Because the original strap is genuine cow leather, it should not be described as nylon, fabric or synthetic leather.
LumiBrite and Everyday Legibility
LumiBrite is applied to the hands and indexes to assist with time reading in darker conditions. The combination of oversized Arabic numerals, broad hands and a contrasting red GMT indicator separates the primary time display from the secondary 24-hour display.
The SBSC013 does not use a rotating dive bezel. Its fixed 24-hour bezel is specifically intended to work with the GMT hand for dual-time reading.
See-Through Case Back
A see-through screw case back reveals the Caliber 4R34 and its automatic winding rotor. The transparent back highlights the mechanical construction while retaining the secure screw-back arrangement specified for the model.
The orientation of the case-back markings may vary between individual watches because of the manufacturing process.
10-Bar Water Resistance
The SBSC013 provides 10-bar water resistance and magnetic resistance rated at 4,800 A/m on the matching international model. These specifications support everyday use and general outdoor activity.
The leather strap should nevertheless be protected from unnecessary moisture because repeated exposure to water can shorten the service life of natural leather. The SBSC013 is also not an ISO-certified diving watch and should not be marketed as a professional diver.
Japanese Reference and International Counterpart
SBSC013 is the reference used for the Japanese domestic market. The matching international version is sold as SSK025 or SSK025K1. Both models use the same black-coated case, matte-black dial, red GMT hand, leather pass-through strap, Caliber 4R34 and core dimensions.
The SBSC013 is manufactured in Japan. However, because the corresponding SSK025 is officially distributed internationally, the design should not be described as exclusive to Japan.
This is a regular-production model. SEIKO does not identify it as a limited edition, numbered edition, collaboration or retailer-exclusive release.
Key Highlights
- Japanese-market SEIKO 5 Sports Field Series model SBSC013
- International counterpart SSK025/SSK025K1
- Matte-black dial with a contrasting red GMT hand
- Black hard-coated stainless steel case
- Black cow-leather pass-through strap
- Mechanical automatic Caliber 4R34 with manual winding
- 24-hour dual-time display with a fixed GMT bezel
- Approximately 41-hour power reserve
- Compact 39.4 mm case diameter
- Curved Hardlex crystal
- LumiBrite on the hands and indexes
- See-through screw case back
- 10-bar water resistance
- Made in Japan
- Regular-production model, not a limited edition
Product Specifications
| Brand | SEIKO |
|---|---|
| Collection | SEIKO 5 Sports |
| Series | Field Series |
| Style | Field Street Style GMT |
| Model | SBSC013 |
| International Reference | SSK025 / SSK025K1 |
| Market | Japanese Domestic Market reference |
| Gender | Men’s |
| Dial Color | Matte black |
| GMT Hand | Red five-sided 24-hour hand |
| Caliber | 4R34 |
| Movement | Mechanical automatic with manual winding |
| Frequency | 21,600 vibrations per hour (6 beats per second) |
| Jewels | 24 |
| Power Reserve | Approximately 41 hours |
| Accuracy | +45 to −35 seconds per day when worn on the wrist at 5°C to 35°C |
| Functions | 24-hour dual-time hand, date display and stop-seconds |
| Case Material | Stainless steel with black hard coating |
| Case Diameter | 39.4 mm |
| Lug-to-Lug | 47.9 mm |
| Thickness | 13.6 mm |
| Crystal | Curved Hardlex |
| Bezel | Fixed black bezel with 24-hour scale |
| LumiBrite | Hands and indexes |
| Strap Material | Black cow leather |
| Strap Construction | One-piece pass-through strap |
| Band Width | 20 mm |
| Maximum Wrist Circumference | Approximately 225 mm |
| Water Resistance | 10 bar |
| Magnetic Resistance | 4,800 A/m |
| Weight | Approximately 79 g |
| Case Back | See-through screw case back |
| Country of Manufacture | Japan |
| Release Date | January 12, 2024 |
| JAN | 4954628465412 |
| Edition | Regular production; not a limited edition |