Description
SEIKO SELECTION Space Brothers Mutta Nanba SBJG023 Limited Edition
The SEIKO SELECTION SBJG023 is a Japanese Domestic Market digital quartz watch created in collaboration with the manga Space Brothers. Supervised by series creator Chūya Koyama, this limited-edition model is inspired by Mutta Nanba and the scene in Volume 40 where the Nanba brothers reunite on the Moon.
Design Inspired by Mutta Nanba
The silver-colored exterior takes its inspiration from the spacesuit worn by Mutta Nanba. Its black-plated octagonal bezel emphasizes the retro-futuristic case shape and gives the model a distinctive appearance separate from the gold-colored Hibito Nanba version.
The eight-sided bezel also complements the watch’s eight selectable digital functions. A one-piece symbol associated with the “PIECE OF CAKE” concept appears at the 12 o’clock position, connecting the exterior design with imagery from Space Brothers.
Rotary Digital Control
Caliber A824 uses a rotating bezel as a rotary switch for selecting digital modes. This interface provides direct access to the watch’s counter, stopwatch, alarm, timer, calendar and dual-time functions. An internal LED illuminates the digital display when additional visibility is required.
The stopwatch measures in 1/100-second increments for up to 99 hours, 59 minutes and 59 seconds. The timer can be set in one-minute increments for up to 100 minutes. Daily and one-time alarms are included, while the full-auto calendar is programmed through December 31, 2074.
Battery-Operated Quartz Performance
The digital watch is powered by SEIKO Caliber A824, a battery-operated quartz movement with a stated accuracy of ±20 seconds per month. The expected battery life is approximately three years, and a battery-life warning function indicates when replacement is approaching.
Limited-Edition Details
SBJG023 is limited to 824 pieces for the Japanese market. The screw case-back carries the “WE ARE SPACE BROTHERS PIECE OF CAKE” symbol, a “LIMITED EDITION” inscription and an individual serial number.
An additional nylon strap is included for an alternative, space-inspired appearance. The reverse side of the strap carries a “SPACE BROTHERS” logo that can be revealed depending on how the strap is folded. The watch is presented in a special box featuring the scene in which Mutta and Hibito reunite on the Moon.
Stainless-Steel Construction
The stainless-steel case measures 43.5 mm in length, 37.0 mm in width and 10.6 mm in thickness. It is fitted with Hardlex crystal, a screw case-back and a stainless-steel bracelet secured by a push-button three-fold clasp. The watch weighs approximately 109 g and accommodates wrists up to approximately 195 mm.
The SBJG023 provides enhanced water resistance for daily use at 10 bar. Its compact digital format, rotating mode selector and collaboration-specific exterior combine practical functions with a design rooted in the retro-futuristic world of Space Brothers.
Japanese Domestic Market Model
SBJG023 is a Japanese Domestic Market collaboration model with a Japan-specific reference, domestic release and limited allocation of 824 pieces. The JDM designation identifies its intended market and does not mean that the watch was manufactured in Japan; authorized retail specifications identify China as the country of manufacture.
Key Highlights
- Official Space Brothers collaboration supervised by Chūya Koyama
- Design inspired by Mutta Nanba and his silver-colored spacesuit
- Black-plated octagonal rotating mode-selector bezel
- Battery-operated digital quartz Caliber A824
- Counter, stopwatch, alarm, timer and dual-time functions
- Full-auto calendar through December 31, 2074
- Internal LED display illumination
- Approximately three-year battery life
- Limited to 824 pieces in Japan
- Individually numbered case-back with collaboration artwork
- Additional nylon strap with Space Brothers logo
- Special collaboration presentation box
Product Specifications
| Brand / Collection | SEIKO SELECTION |
|---|---|
| Series | S Series / International Line |
| Model | SBJG023 |
| Collaboration | Space Brothers |
| Character Model | Mutta Nanba |
| Market | Japanese Domestic Market |
| Country of Manufacture | China |
| Edition | Space Brothers Collaboration Limited Edition |
| Limited Quantity | 824 pieces in Japan |
| Watch Type | Battery-operated digital quartz watch |
| Display | Digital |
| Exterior Color | Silver with black bezel |
| Case Dimensions | 43.5 mm length × 37.0 mm width × 10.6 mm thickness |
| Weight | 109 g |
| Case Material | Stainless steel |
| Bezel | Black-plated octagonal rotating bezel with rotary mode-selection function |
| Crystal | Hardlex |
| Case-Back | Screw case-back with collaboration symbol, “LIMITED EDITION” inscription and individual serial number |
| Band / Bracelet | Stainless-steel bracelet |
| Additional Strap | Nylon strap with “SPACE BROTHERS” logo on the reverse side |
| Clasp | Push-button three-fold clasp |
| Band Width | 20 mm |
| Compatible Wrist Size | Up to approximately 195 mm |
| Movement Type | Battery-operated quartz |
| Caliber | A824 |
| Battery Life | Approximately 3 years |
| Accuracy | Average ±20 seconds per month |
| Stopwatch | 1/100-second measurement up to 99 hours, 59 minutes and 59 seconds |
| Alarm | Daily alarm and one-time alarm |
| Timer | Adjustable in one-minute increments up to 100 minutes |
| Calendar | Full-auto calendar through December 31, 2074 |
| Functions | Rotary switch, counter, dual time, battery-life warning and internal LED illumination |
| Water Resistance | Enhanced water resistance for daily use at 10 bar |
| Special Packaging | Space Brothers presentation box depicting the Moon reunion scene |
| Release Date | November 14, 2025 |
| JAN Code | 4954628471178 |