Moonlight on the emblematic birch

The noble birch tree has become a totem of Grand Seiko's symbiosis with nature, and this brooding reference carries that theme with a dial inspired by moonlight on this distinctive textured surface. This 10-beat, manual-winding mechanical watch is based on the “Evolution 9 Style,” a unique design grammar that takes the fusion of Grand Seiko’s spirit with the aesthetic sensibilities of Japan to a higher level. Its textured, navy-colored dial evokes the bark of a white birch tree illuminated by the moon. Featuring a slender stainless steel case that is a mere 9.95mm thick, the creation has an appearance worthy of a Grand Seiko dress watch. The bezel is refined, with a narrow profile that complements the lugs, whose clean lines are echoed on the dial by the indexes. The manual-winding movement is the Caliber 9SA4, which features a high number of vibrations, 10 per second, to maintain a stable level of accuracy, as well as a generous power reserve of up to 80 hours.

The movement achieves a higher winding efficiency thanks to a rearrangement of the gear train and redesign of the parts, so that Caliber 9SA4 achieves a power reserve of 80 hours with 15 percent fewer crown rotations than are required to achieve the same power for Caliber 9SA5 when winding it by hand.