Chronotheory & Co.

Chronotheory & Co. is the independent watchmaking project born from Chronotheory — a watch salon and retailer in Ginza, Tokyo, whose futuristic interior evokes a spacecraft and whose stated concept is 'a joyful voyage through watchmaking.' Where the salon trades in watches and ideas, the '&Co' project is an act of cultural preservation: a declared mission to carry the aesthetic heritage of watchmaking's past into the future through precisely engineered contemporary pieces that look backward without sacrificing a single aspect of modern usability. The logo's typography — a deliberate quotation of 1940s watch dial lettering — states the intent immediately. The project was conceived by Naoto Watanabe, founder of Chronotheory and the series' planning director and case designer, who trained originally as an audio engineer before building a career in graphic design at a magazine publishing house and then a major advertising agency, before joining an airline IT venture and ultimately founding the salon in 2021. He writes as an external contributor to Chronos Japan. The watchmaker responsible for movement finishing is Yutaro Iizuka — a graduate of Hiko Mizuno College of Jewelry, where he won the Walter Lange Watchmaking Excellence Award 2018 for a bimetal-switch temperature alarm clock. After training at a watch repair company he joined Chronotheory in 2021; he too contributes to WEB Chronos and is a member of the GPHG Academy.

The first reference, the AV-98 — short for Advanced Vintage 6498 — takes the ETA 6498-1 as its base movement and completely reimagines both the watch built around it and the movement itself, under the theme of an 'antique-design watch that is practically usable': a dress watch drawing from the detailing vocabulary of the 1930s to 1950s that integrates without effort into contemporary casual or business dress, and can be worn fearlessly in the subtropics where sudden downpours and high humidity are constant realities. The case is produced by Kyowa Seiko Co., Ltd. — the company that also manufactures and runs the independent brand MINASE — and is a masterpiece of Japanese machining: a 42mm × 9.1mm stainless steel form, lug-to-lug 49mm, with a three-dimensional curved case whose mid-case is machined entirely from a single billet rather than being welded, eliminating all soldering marks entirely. After CNC machining, skilled craftsmen apply Zaratsu polishing and hand polishing to achieve mirror surfaces with sharp edges and no irregular distortion — the same standard applied to MINASE cases, which are celebrated among collectors for their surface finishing quality. The lug tops are raised one step above the mid-case top surface to create developable surfaces (ruling surfaces with no twist), aligning the lug reflections into perfect straight horizontal lines when viewed from 3 and 9 o'clock. A box-type sapphire crystal and a screw-back with rear sapphire crystal are sealed with gaskets at every joint — box crystal to bezel, bezel to case, case to screw-back, screw-back to rear crystal — delivering genuine 6ATM water resistance in an antique-inspired package. Dual anti-reflective multi-coating is applied to both crystals.

The dial is produced by Shoko-sha, a manufacturer of high-end dials for Japan's leading watchmakers: a 0.4mm-thick brass construction with a small seconds area machined as an integral stepped recess rather than applied separately — the upper surface is polished to the final mirror or hairline finish, the step edge is sharp, and the small seconds recess is rhodium plated and lacquered after machining. Breguet numerals at 0.15mm thickness — equivalent to the fineness of pocket watch era numerals — are applied as individual three-dimensional parts, designed in-house from scratch using 1930–40s references adjusted for balance and legibility on the watch dial rather than from any general-purpose typeface. The three colourways are Piano Forte Black (black mirror lacquer, yellow gold indices and hands), Strato Navy (blue mirror lacquer, silver indices and hands), and Timpani Rose (bronze hairline, silver indices and hands).

The ETA 6498-1 CT Edition is Iizuka's personal performance: every bridge shape has been formed entirely by hand filing — no CNC — producing original profiles, angled returns, and 0.6mm-wide bevels. The bridges are then mirror-polished, put through a proprietary finishing process, and coated with a semi-circular Côtes de Genève pattern applied by a wooden rotating tool. Unlike the standard quarter-arc stripes, this half-circle variant uses minimal cutting pressure, leaving the bridge surface without visible relief variation for a smoother, more refined visual character. All finished bridges and mainplates receive 24-karat pure gold plating rather than the rhodium standard — producing an exceptionally vivid, warm gold colour visible through the caseback. The main gear train wheels — second, third, and fourth wheel — have bevels applied to the spoke (Amida) sections as well, and the pallet fork and pallet cock both receive wide chamfers, imparting the three-dimensional sculptural quality of the finest pocket watch movements. The winding and time-setting components — crown wheel, ratchet wheel, setting wheel, intermediate wheel, and click — are individually reshaped and polished to the tooth tips, creating a winding sensation entirely free of roughness or vibration and a time-setting action smooth enough that the gear train's existence cannot be felt. A Trio-Vis regulation system is used in place of the standard regulator.

The stated ambition is to transform the daily ritual of hand-winding from a chore into a moment of genuine pleasure. The watch ships with Chronotheory's proprietary full-leather 'WATCHCUBE' carrying case — all-leather exterior and interior with built-in cushioning and a zipper construction that prevents the zipper from contacting the watch — replacing the decorative but impractical wooden and cardboard boxes that Watanabe regards as unnecessary. Production is planned at three pieces per six-month window, one per colour, allocated by lottery. A three-year warranty is included.