Model: Credor “Z Reference” GZBD007 / 6899-0080
Year: 1998
Limited Edition: 20 Pieces
Features:
The Origin. In 1996, two of Seiko’s most decorated employees created a watch that shaped the future of Japanese haute horlogerie. That watch in question was the Credor GBBD - a skeletonised dress piece in solid platinum, housing the razor-thin 6899 calibre. Mamoru Sakurada designed, built, and assembled the movement, while Kiyoshi Terui engraved every available millimetre by hand. To them, it was more than just a watch - it was a signal to the watch world that Seiko was upping its game.
The Partnership. A few years later, in 2004, Sakurada and Terui would become two of the three founding members of the now-famous Shizukuishi Watch Studio - the birthplace of all mechanical Grand Seikos and select Credors. Today, they’re often considered to be two of the greatest artisans in Seiko’s modern history, and this watch has the distinct honour of being their first known partnership.
The Reference. This not your typical Credor skeleton - it’s a 1 of 20 “Z Reference” GZBD007. Visually, it looks almost identical to the GBBD987, but it was made exclusively for one of Seiko’s oldest and most prestigious retailers - the Chino Watch Shop. Seiko would go on to buy Chino in 2019, before eventually rolling it into one of its larger subsidiaries. But there was a brief period in the late ’90s and early ’00s when Credor made a handful of references exclusively for Chino. So what is the difference?
The Metal. It was the first white gold skeleton produced by Credor - in fact, it took almost 15 years for Credor to make another one. During that period, Credor exclusively used either yellow gold or platinum for its skeleton watches, with the only exception being the GZBD007 on offer today.
The Difference. Don’t get me wrong, white gold and platinum are meaningfully different materials, but is swapping one silvery precious metal for another the most mind-blowing basis for an exclusive? Absolutely not. But it should be noteworthy for collectors, especially when we consider that after ignoring white gold for almost 15 years, Credor has done a complete U-turn and now seems to prefer it over platinum when it comes to modern Skeletons.
The Build. Their work on the 6899 series remains a technical benchmark. Assembling the movement was a reactive process for Sakurada - piece by piece, each component is shaped and fitted on the fly against the one that came before it. Tolerances of 0.03mm are judged by touch alone. While the calibre itself is only 1.98mm thick, some sections are as thin as 0.25mm. In order to maintain structural integrity, Terui works to a maximum engraving depth of 0.15mm – all checked by his touch, with a sensitivity refined over decades.
The Recognition. For their technical achievements, both men were awarded the Yellow Ribbon - a rare distinction granted by the Japanese Government to individuals whose mastery of an industry is considered irreplaceable.
The Design. And yet, for all its technical brilliance, the GZBD007 remains poetic. Its skeletonised bridges were shaped to resemble bamboo stalks swaying in the wind, and Terui’s engravings feature traditional Japanese motifs, including the chrysanthemum flower - the Imperial Seal of Japan.
The Result. The result is not just a rare Credor, or an early example of the 6899. Its connection to both Seiko and Japan is obvious - humble in scale, immense in meaning, and rooted in the lives of two master craftsmen at the start of a shared journey that altered the trajectory of the watch company forever.
Specifications:
Condition: In good condition overall. Just serviced. Some hairlines and light handling marks can be seen on the gold case. Original strap and buckle.
Scope: No box, but comes with service papers
Movement: 6899 Manual-wind
Dimensions:
- Case Width: 33.5mm
- Lug to Lug: 38.9mm
- Case Thickness: 5.5mm
- Lug Width: 18.0mm
