The Japanese method of time-telling was based on the natural day, from dawn to dusk. Day and night were each divided into six seg-ments of different length. The dial begins with number "9" and goes backwards (9,8,7,6,5,4), because the Japanese considered that 9 was a magic number. Since a clock was an important and mys-terious object in itself, it was thought desirable that the mystical number be present in every hour, and be directly attributed to mid-night and noon. The other hours were multiplied by number 9 and the second digit of the product was taken as the clock hour (for example, hour 2 was in fact 8 because 2 x 9 = 18). In Japan, every hour had a name, similar to our days of the week, which are not numbered from 1 to 7, but have names: Monday to Sunday. Tradi-tional Japanese hours were named after the Chinese zodiacal signs, midnight (bottom of the dial) being "rat", midday (top of the dial) "horse", sunrise (to the left) "hare", sunset (to the right) "cock", and so on. The early Japanese clocks had fixed hours, while later ones had movable hour blocks. The Japanese used three calendar systems. The one implemented in this clock is based on reckoning the time of cycles of 60 years. This was done by combining the names of the 12 signs of the Zodiac (Junishi) with the signs of the particular element (Jukkan), called the "Ten Celestial Stems". Timepieces with mechanical escapements were introduced to Japan by the Jesuits in the 16th century. The Japanese soon began producing their own clocks at the beginning of the 17th century Such clocks with double calendars are rare. One is shown in "Japanese Clocks" by N.H.N. Mody, Japan, 1967, plate 27, and another in the 3rd volume of Tardy?s "Provinces et Etranger", Paris, 1964, p. 426.