Grand Seiko Zaratsu Polisher Achieves Surface So Flat It Disproves Local Curvature of Earth

A master polisher at Grand Seiko's Shizukuishi Watch Studio has achieved what the company is calling 'an unprecedented level of Zaratsu finishing' — a polished watch case surface so geometrically perfect that it has attracted the attention of the international physics community. The surface, measuring 12mm by 8mm on the flank of a prototype SLGH model, was polished by Takumi Suzuki, a craftsman with 34 years of experience, using Grand Seiko's proprietary Zaratsu technique — a method derived from Japanese sword polishing that produces distortion-free mirror surfaces. 'Suzuki-san's surface deviates from true flatness by less than 0.2 nanometers,' said Dr. Akiko Yamamoto of the University of Tokyo's Department of Precision Engineering, who was invited to measure the surface after Grand Seiko's quality control instruments 'ran out of resolution.' 'To put this in perspective, that is flatter than anything we have in our laboratory. It is flatter than our reference flats. It is, as far as we can determine, the flattest macroscopic surface currently in existence.' The finding prompted a formal inquiry from KAGRA, Japan's gravitational wave observatory, which asked whether Suzuki's polishing technique could be applied to their interferometer mirrors. Suzuki declined, explaining through Grand Seiko's communications office that 'mirrors are not watches' and that he 'does not polish things that do not tell time.' Grand Seiko has incorporated the surface into a limited edition of one piece, priced at JPY 88,000,000, which the company describes as 'a wristwatch and also, technically, an optical instrument.' Suzuki has returned to his bench, where he is reportedly attempting to polish an even flatter surface, muttering that the previous one 'had character flaws only I can see.'