Seiko Institute of Horology / Water clock
The Seiko Institute of Horology (now The Seiko Museum) was opened in 1981 as part of a project to commemorate the 100th anniversary of the founding of Seiko. The museum displays research materials related to time and timepieces produced in Japan and other countries around the world. (For more information, see the February 2009 issue of the PR magazine pla-topia.) http://museum.seiko.co.jp/
A water clock said to have been used by Emperor Tenchi. Four containers are in series, and water flows through them at a constant rate. The lowest container housed an arrow fixed to a float and the arrow came to float as water collected. The time was read from this. It is said that Emperor Tenchi reported the time with this watch and because that day was June 10, 671, June 10 in latter years was designated "Time Memorial Day"
