Elegant decorations, intricate mechanisms, and stunning mechanical devices. The "Prince Investiture Celebration Clock" is a masterpiece from the Taisho era, expressing the wisdom, skill, and aesthetic sense of engineers, and was created to express congratulations on this auspicious Imperial event. It was completed by the Shokosha Watch Research Institute, the predecessor to Citizen Watch. After three years of restoration work, it has been restored to its former glory. Taisho and Reiwa. We introduce the hard work of the engineers who connected the dominance of 100 years of history, and the unknown story of this major project.
This large weight-type mechanical clock was presented to Crown Prince Hirohito (later Emperor Showa) by the City of Tokyo in 1916 (Taisho 5) to celebrate the Crown Prince's investiture ceremony. It stands 220cm tall and weighs 280kg. It was conceived and designed by faculty members at the Tokyo School of Fine Arts (now Tokyo University of the Arts). Construction was difficult, but thanks to the efforts of Kamekichi Yamazaki and other engineers at the newly founded Shokosha Watch Laboratory (now Citizen Watch Co., Ltd.), it was successfully completed. For this restoration, the exterior was handled by the Tokyo University of the Arts Graduate School of Conservation and Restoration Crafts Laboratory, and the machinery was handled by Citizen Watch Co., Ltd.
Tomoyo Takai: Interview and text Text by Tomoyo Takai
Edited by Yuto Hosoda (Chronos -Japan)
[Article published in July 2022 in the Japanese edition of Khronos]
The origin and the apex
"Decorative Clock Celebrating the Establishment of the Crown Prince"
An old clock that will rewrite the history of Japanese clocks has suddenly appeared. It is a unique piece that is unparalleled anywhere in the world. It is the Crown Prince Investiture Ceremony Clock. It is a large mechanical clock that was presented by the City of Tokyo to celebrate the investiture ceremony of Crown Prince Hirohito (later Emperor Showa) held in 1916 (Taisho 5).
Its imposing presence is befitting a celebration of the Imperial Family's auspicious occasions. The teakwood cabinet is adorned with elegant ornaments throughout, and its numerous mechanisms captivate the viewer. At the top of the palace-style structure, a child-dancing doll, performing the "Kanzoraku" dance, a form of music performed at celebratory occasions, moves across the stage, raising its arms toward a large gong. Bells ring out in time with the drumming, and a dove near the dial spreads its wings and coos. Then, as people fall asleep, the seven-day screen attached to the cabinet advances to the next day, like an aesthetic picture-story show.
The Imperial Clock was presented to the Imperial Court in 1921. It remained hidden from the public eye for nearly 100 years. Now, at the request of the Prince Akishino family, it has been returned to the place where it was made. The reappearance of this Imperial Clock has brought two surprises to the watch industry. First, it reveals the existence of a surprisingly advanced aesthetic sense and the sophisticated technology that made it possible, even in the early days of Western-style Japanese-made clocks. Second, it reveals the important, unknown responsibility that the Shokosha Watch Research Institute, the predecessor of Citizen Watch, had fulfilled shortly after its founding.
In 2019, Citizen received a call from Tokyo University of the Arts, asking to undertake the mechanical repair of a decorative clock made by Shokosha. However, this news came as a complete surprise to Citizen. At the time, the company's first known product was a 16-inch pocket watch, released in 1924. There was no information in the company history about any watches made before that.
When the Imperial Clock was delivered to Tokyo University of the Arts by the Imperial Family, it was in a state far different from when it was first made. It was severely damaged and deteriorated. The severely distorted roof was covered in blue rust reminiscent of water stains, and the bottom section of the case had black burn marks. The reason for this is unclear, but it is believed to have been carried out in a frantic attempt amidst flames during a crisis that broke out within the last century.
In 2019, the mechanical components were transferred from Tokyo University of the Arts to the restoration room at the Citizen Museum. The restoration room had opened just two weeks prior. Coincidentally, the decorative clock was the first item to be requested for repair. The main person in charge of the restoration work was Ushiyama Tenka, a young technician who had been with the company for seven years at the time. He was backed up by veterans Sakita Eiichi and Nakazawa Kiyoshi. This system also served to strengthen the transfer of skills.
The work began by disassembling the car to check its condition and analyze it. No major damage was found to the gears or bearings, and the plan was to restore it by replacing missing parts, removing rust, plating, reassembling, and adjusting. However, the task at hand was unknown, with no blueprints. The entire process involved the accumulation of painstaking effort. Even the screws, for example, were made to the Lebenherz standard, a special standard that was used in Germany for a very short period from the end of the 19th century. The corroded steel chain, approximately 1mm wide, was also made in-house, and the eccentric cam, the optimum dimensions of which were unknown, had to be remade multiple times.
It also took time to determine the power source of the weights, which weighed a total of 58.2 kg, which was initially unknown. The list of details would be endless, and of course, it goes without saying that it took a lot of effort to perfectly operate a mechanism that didn't work. This restoration project, which was successfully completed after three years of hard work, will be an honor that will be passed down to future generations.
The sight of the gleaming gears packed together is truly magnificent. The mechanical components are mainly concentrated behind the dial, and the case covering both sides and the back is made of glass. In other words, the design of this mechanical component is primarily intended for viewing. At least to my knowledge, this is the only Japanese-made watch from the Taisho era that is so-called transparent, in order to "show off" the mechanism. In fact, the design philosophy that supports this is evident everywhere.
What stands out most are the three crankshafts arranged diagonally. These are used to move the child dance puppet around the stage. Also unique are the three roller shafts that run horizontally across the center of the machine. These are used to send power to the various parts of the puppet, such as raising and lowering its arms, and to drive the pigeons, bellows, and drums. At the top of the hour, a link structure is used to swing the upper rod back and forth, creating a dynamic performance. Other unique features, although located within the cabinet, include the seven-day screen, which resembles an endless track system, and the pigeon structure, which receives power via a wire that runs along the base.
The watch gear train itself is a standard structure with a pinwheel escapement. Link mechanisms and cam mechanisms that transmit power to each mechanism are cleverly incorporated into this. As it is not a modification of an off-the-shelf product, all of the parts are handmade. Surprisingly, it is worth noting that the escape wheel teeth and all of the gears are fastened with screws. This is thought to have been done with ease of maintenance in mind. The design concept of the decorative clock is a high-level fusion of traditional Japanese and Western techniques.
