Miyota 9039 Explained: The Movement Inside Every KOMPAS
If you turn a KOMPAS over, the heart of the watch is a Japanese Miyota 9039 automatic movement. Here's what that means, and why we chose it.
What is the Miyota 9039?
Miyota is the movement-making arm of Citizen, one of Japan's largest watchmakers. The 9000 series is Miyota's premium family of mechanical movements: slim, high-beat and built for long service. The 9039 is the time-only version, with hours, minutes and seconds and no date window. That keeps the dial clean, which is exactly what a field watch needs.
Key specifications
Type: Mechanical, automatic (self-winding) with hand-winding
Frequency: 28,800 vibrations per hour (4 Hz)
Jewels: 24
Power reserve: Around 42 hours
Functions: Hours, minutes, central seconds
Hacking seconds: Yes
What those specs mean in daily life
Automatic winding. A rotor inside the watch turns as your wrist moves and winds the mainspring. Wear it daily and it keeps itself running.
Hand-winding. If the watch has stopped, turn the crown clockwise 20–30 times to give it a start before setting the time.
28,800 vph. The higher the beat rate, the smoother the seconds hand sweeps. At 8 ticks per second, the 9039's seconds hand glides rather than jumps.
Hacking seconds. Pull the crown out and the seconds hand stops, so you can set the time to the exact second.
42-hour power reserve. Take the watch off on Friday evening and it will still be running on Saturday afternoon.
Accuracy: what to expect
A mechanical watch is a tiny machine, not a quartz circuit, so it gains or loses a few seconds a day. How much depends on position, temperature and how fully wound it is. Small daily variation is normal for any mechanical watch. If yours suddenly starts gaining or losing noticeably, get in touch and we'll help.
How to look after it
Wear it. Regular movement keeps it wound and lubricated.
Avoid strong magnets like speakers, bag clasps and phone cases with magnets. Magnetism can make a mechanical watch run fast.
Keep the crown pushed in around water.
Service it every few years to clean and re-lubricate the movement.
Why we chose it
We wanted a movement that is proven, serviceable anywhere in the world and smooth enough to match the dial it sits behind. The Miyota 9039 ticks all three boxes.
