For convenience in describing wadokei in this web strand, they can be considered in four basic categories. All wadokei feature temporal time, either by varing the rate of the clock, or adjusting the hour markers.
Category 1 – Early European-Style Lantern Clocks
This first category are clocks based on the early-European “Lantern Style” brought to Japan – mainly by the Dutch. The construction of these clocks are all basically the same, and are described by the way in which they were mounted:
- Dai-dokei – Lantern clocks on four legged wooden stands
- Yagura-dokei – Lantern clocks on wooden pyramid stands
- Hashira-dokei – Lantern clocks on wooden wall brackets
- Kake-dokei – Lantern clocks with wall hook loops
Category 2 – Uniquely Japanese Style Clocks
The second category are clocks that relate to the uniquely Japanese method of indicating time based on the fall of the weight of the clock’s going train. A very logical principle but one never adopted in the rest of the world.
- Shaku-dokei – Pillar clocks of which there were various versions.
Category 3 – Japanese Adaptations of other Clocks
The third category are clocks (or watches) based on the adaptation of later-European styles and mechanisms to meet specific Japanese requirements. They include:
- Makura-dokei – Mantle clocks with mainspring
- Kane-dokei – Bell mounted clocks with mainspring
- Inro-dokei – Belt worn watches with mainspring – based on English pocket watches
- Keisan-dokei – Desk clocks or Doctors’ clocks – based on English pocket watches
- Pocket Watch – Direct adaptations of mainly English pocket watches
Category 4 – Special Japanese Clocks
In addition to the three main categories above, and as might be expected, there were several special Japanese clocks. Two significant examples are:
- Mannen-dokei or “Thousand-Year Clock” – a one off masterpiece
- Suiyokyugi-dokei – Astronomers’ clocks based on shaku-dokei
Note: Non-mechanical timepieces were:
- Zasshu-dokei – Pocket sun-dial
- Koban-dokei or Jokoban – Incense clock