Citizen has a long legacy of creating rugged, dependable tool watches, and few embody that spirit more than the Citizen Promaster Fujitsubo Automatic – NB6021-17E. Combining Japanese engineering, ISO-certified dive credentials, and a fascinating history, the Fujitsubo is quickly becoming a must-own piece for serious watch collectors and adventure seekers.

The Story Behind “Fujitsubo”

The nickname “Fujitsubo” (Japanese for barnacle) comes from a remarkable real-world endurance test. In 1983, a Citizen diver’s watch was discovered after spending years submerged in the ocean, encrusted with barnacles. Astonishingly, when it was cleaned, it was still running perfectly.

This real-life durability test cemented Citizen’s reputation as a leader in dive watch reliability—and inspired the Fujitsubo name for this modern re-creation.

Design and Case

The NB6021-17E features a 41mm stainless steel case with a sleek brushed finish that balances tool-watch ruggedness with refined style. The black dial with luminous hands and markers ensures exceptional visibility underwater or in low light.

The case construction is slim and comfortable, with a 12.3mm thickness, making it versatile enough for daily wear, while still built to handle professional dive conditions.

The watch is paired with a durable black polyurethane strap that can handle saltwater exposure and tough environments.

Automatic Movement

At its heart, the Fujitsubo houses the Citizen Caliber 9051 automatic movement, offering:

42-hour power reserve

Hacking seconds & hand-winding

24 jewels for smooth operation

The Caliber 9051 is also anti-magnetic, a crucial feature for divers and modern professionals exposed to magnetic fields that can affect accuracy.

Professional Diver Features

The NB6021-17E is not just a stylish watch—it’s a true ISO-certified diver’s instrument. Features include:

200M water resistance (ISO compliant for scuba diving)

Unidirectional rotating bezel for timing dives

Sapphire crystal with anti-reflective coating for scratch resistance and clarity

Screw-down crown and caseback for enhanced water protection

Super-LumiNova lume for legibility in total darkness

Why the Fujitsubo Stands Out

Inspired by a legendary story of durability.

Compact and wearable size at 41mm, compared to bulkier dive watches.

Reliable automatic movement with anti-magnetic protection.

Exceptional value for money compared to Swiss competitors offering similar specs.

Top Questions & Answers About the Citizen Promaster Fujitsubo NB6021-17E

Q1: Why is it called the Fujitsubo?
It’s named after the barnacle (“Fujitsubo” in Japanese) to honor a Citizen diver watch found encrusted with barnacles after years in the ocean—still ticking.

Q2: Is the Citizen Fujitsubo ISO certified?
Yes, the NB6021-17E is ISO 6425 certified for professional scuba diving.

Q3: What movement is in the Citizen Fujitsubo?
It uses the Citizen Caliber 9051 automatic movement, offering a 42-hour power reserve and anti-magnetic resistance.

Q4: How big is the Citizen Fujitsubo?
The case is 41mm wide and 12.3mm thick, making it compact for a dive watch but still robust.

Q5: Can the Fujitsubo be worn daily?
Absolutely. Its slim design and versatile look make it perfect for everyday wear, not just for diving.

The Citizen Automatic Promaster Fujitsubo – NB6021-17E is more than just a dive watch—it’s a piece of Citizen’s history reborn. With its rugged ISO-certified build, anti-magnetic movement, sapphire crystal, and legendary inspiration, it offers everything you’d want in a professional diver’s tool while remaining stylish and wearable day-to-day.

If you’re looking for a watch that combines heritage, reliability, and modern performance, the Fujitsubo deserves a place on your wrist.

Discover Citizen Promaster watches like the Fujitsubo at GDGWatch.com and experience the strength of Japanese watchmaking.