Yosuke Sekiguchi Piece Unique Primevère, Steel

Yosuke Sekiguchi's Primevère has now debuted at auction, but here we have a wild Piece Unique about to follow. This one is highlyg distinct: No. 36, completed in 2026 and catalogued as a pièce unique, the ‘Interprétation du Japon’. The 39.5mm by 12mm steel case and white grand feu enamel dial with Roman numerals are familiar Primevère. The small seconds is not. Its sub-dial is dark red aventurine grand feu enamel, a red disc on a white field that, given the name, reads as the Hinomaru with remarkable elegance.

Sekiguchi was born in Gunma in 1980 and left Japan at 23, first for France to learn the language, then Switzerland. Refused a watchmaking school place over his visa, he earned his diploma as an independent candidate. He spent 2008 to 2011 at La Joux-Perret on split-seconds chronographs and tourbillon cages, then five years at Christophe Claret, completing a detent escapement tourbillon pocket watch of his own, made from scratch, before he left. He set up independently, more quietly than most, in Le Locle in January 2020.

Calibre YS-Y01 is modelled on an 1871 Jules Jürgensen pocket watch that Sekiguchi restored, then reverse engineered. It follows the "Le Locle" style ébauche LeCoultre once supplied to Jürgensen: six arched German silver bridges, cut with a saw and finished by hand. The regulator index is dramatically long and black-polished, the escape wheel and pallet lever sit under gold caps, and the winding click spring is bent into an omega. It beats at a pocket watch 18,000 vph with 40 hours of reserve. A hidden Incabloc is the one concession to modernity. He saws and files the spade hands himself; the case he designed is made by Stila.

Production is quoted at 15 to 20 watches per year. The numbers hint at fewer: this 2026 watch is No. 36, and a 2025 example sold by Phillips was No. 30. Retail has risen from CHF 51,000 in steel at launch to CHF 88,000 for a recent white gold edition. At Phillips, pink gold examples made CHF 95,250 in Geneva last November and HK$1,143,000 in Hong Kong this May. This is the first piece unique to debut at auction and will be one to watch.