Wound by a spring, paced by a foliot. Built from a book of 1796.
Hosokawa Hanzō (Yorinao, c.1741–1796), a calendar scholar from Tosa on Shikoku island, published Karakuri Zui, the “Illustrated Compendium of Clever Machines”. The first volume covers four kinds of Japanese clocks; the second opens with this tea-serving doll. Makers had guarded such drawings as trade secrets, and the book is regarded as Japan's first published work of mechanical engineering. For scale: it appeared twenty years after the American Declaration of Independence and a generation after the Jaquet-Droz automata in Switzerland.
Wood, thread and whale baleen. In the reconstructions by Tamaya Shōbei IX, seven woods each do one job: hinoki cypress for the face, cherry for the body, karin (a padauk-like hardwood) for the gears, red oak for the axles, and boxwood, ebony and bamboo for the speed regulator. Japan could not yet make steel springs, so baleen from a right whale's upper jaw was shaved to an even thickness and coiled into a mainspring.
Put a cup of tea on the tray and the doll glides to the guest. Lift the cup and it stops. Set the empty cup back and it turns on the spot and returns. It was parlour entertainment, a device that got people talking. About 30 cm tall was typical.
The earliest examples trace to the 17th-century clockmaker Takeda Kiyofusa (Takeda Ōmi). Tanaka Hisashige (1799–1881), nicknamed “Karakuri Giemon”, built tea-serving dolls and an archer boy, then the Myriad-Year Clock, often called the masterpiece of Japanese clockmaking. The workshop he opened in Tokyo became a forerunner of Toshiba.
The Edo-period dolls that survive differ mechanically from the book, and no Edo-period doll built to the book's plans has been confirmed. Most dolls on show today are modern reconstructions from the book (Nichimo 1982; Gakken 2002 and 2007). This 3D doll is one more, built to the book's mechanism. The tooth counts are this model's design values, and every number down to the walking speed is computed from them.
| Spring left | – turns |
| Spring force | – % |
| Foliot | – beats/s |
| Escape wheel (12 teeth) | – rpm |
| Second wheel (20 / 12 teeth) | – rpm |
| Spring barrel (48 teeth) | – rpm |
| Wheels (6 teeth · Ø 5 cm) | – rpm |
| Walking speed | – cm/s |
| Turn plate | – |
| Cups served | 0 |
| Distance walked | 0 cm |
| Spring wound | 0 times |
Place a cup on the tray and it walks. Lift the cup and it stops. Put the cup back and it turns around and comes home.
No electricity. A whale-baleen spring and a swinging bar called a foliot, nothing else. The mechanism comes from Karakuri Zui, a Japanese book of 1796, rebuilt in 3D with every number linked, from the gears to the walking speed. The tooth counts are this model's design values.