Grand Seiko Spring Drive 5 Days Caliber 9RA5

This 200m Grand Seiko diver’s watch from the Evolution 9 Collection has a deep black, richly textured dial inspired by the dynamic and sometimes violent tides caused by the Black Stream, or Kuroshio current that surrounds the Japanese archipelago.

The watch exhibits the Evolution 9 Style, a new grammar of design that enhances the Grand Seiko Style established in 1967 and takes the beauty, legibility and comfort of Grand Seiko to a new level. Its Zaratsu polished, distortion-free mirror finish and delicate hairline finish alternate to give the case a quiet and harmonious glow. A new font has been created for the numerals on the bezel especially for the collection. The lugs are wider and the bracelets are more robust and, like the cases, have a low center of gravity to ensure that the watches sit comfortably and securely on the wrist.

The watch’s case and bracelet are made of high-intensity titanium, which is about 30% lighter than stainless steel and brighter in color. The inner section of the rotating bezel is in ceramic to protect the watch from being scratched. The hands and indexes are coated with sufficient Lumibrite to further enhance the legibility of the time at night. The crown guard is carefully designed to avoid being caught on the sleeve in both sport activities and everyday use. 

The watch is powered by the latest Spring Drive movement, Caliber 9RA5, which offers an accuracy rate of ±10 seconds per month and a 5 day power reserve. Caliber 9RA5 has enhanced rigidity and shock resistance thanks to the new layout of the gear train towards the center of the movement and a central bridge that holds them together. This One-piece Center Bridge achieves a shock resistance that meets the ISO standard for diver’s watches. The movement incorporates two barrels which deliver a power reserve of up to 120 hours. They are different sizes so as to deliver the torque required for the five day power reserve while optimizing the use of the limited space within the movement.