Mechanical Open-Heart

The ever-popular Mechanical Open-Heart,
displaying the beating heart of its time-keeping mechanism


Mechanical watches are driven by the force of the mainspring as it gradually unwinds. With an open heart watch you can see the movement of its balance wheel – the beating heart of time – unique to the mechanical system. The watch has a slim case which makes it suitable for business use, and it is a popular choice as a pair design for both men and women.


Knot uses SUS316L – a high-purity, corrosion-resistant, stainless steel used for medical scalpels – as standard. This material is pleasing to wear even for those with metal allergies, as it produces almost no metal ions.

※This does not exclude the possibility that an allergic reaction could still be experienced by some people.

Sapphire glass crystal is made of the same composition as sapphire gemstone. All Knot watches are created using scratch-resistant sapphire glass which measures 9 on the Mohs Hardness Scale, second only to diamond which is rated 10. In addition, mechanical models are coated with a single-sided anti-reflective coating.


Size Image

Male model with 180mm
wrist circumference

Male model with 160mm
wrist circumference

Female model with 150mm
wrist circumference

Female model with 140mm
wrist circumference

Size is an important aspect when selecting a watch. Unlike most mechanical watches, which can often be large and heavy, the CAP-38 is small and light, measuring just 38mm in diameter. It is a popular choice for purchase as a matching pair, suitable for both men and women.
The average adult wrist circumference is 16.8cm for men and 15.4cm for women*. Taller people tend to have larger wrist sizes, even if they are slimmer.

※According to AIST Human Body Dimensions Database 1991-1992.





□Made in Japan
□Movement:EPSON YN84
(6 beats per second/ Power reserve: 40 hours )
□Case:SUS316L / polish
□Glass: sapphire glass
(anti-reflective coating)
□Normal usage accuracy: average -15 seconds to +25 seconds per day
(at room temperature: 5°C to 35°C)
□Water resistance: 5 ATM for everyday life
(hours・minutes・seconds・power reserve・24-hour hand)
□Number of jewels: 22
□Size and weight: Diameter 38mm thickness 11.3mm lug width 18mm weight53g

Silver Case ¥34,650
/ IP Color Case ¥36,850

12 products