In Japan,until around 1868, our ancestors used temporal hour(不定時法,huteijihou) and it is completely different from how to express the time that now we are following. temporal hour: way to express the time following movement of the sun. From the sun rise to sun set, it is called noon(昼、hiru) and From the sun set to the sun rise, this is night(夜、yoru). The length of the noon and night changes following the season. WADOKEI(和時計)has two foliots to indicate the temporal time. The shorter foliot moves at night , and longer one moves at noon.
@@clocklover0110That's fine I can totally understand! I wonder when winter's coming, days are getting shorter and nights longer, in that case you need to adjust the two foliots to keep time, right?
@@KevingerAdr You're right! I'm glad you to understood! Actually 24 or 12 times in a year. I have to move the weight along the 24 solar terms(二十四節気、nijushisekki). Now we rarely use this word. This action was so complicated that there were professional coordinator. around the early 19th, the second way to express the temporal hour time was developed. Because of the first way was so complicated and troublesome. Definitely the length of a day is not change. Therefore they used the moving figure dial(割駒式文字盤、warigomashiki-mojiban). Hourhand turns only once in a day. In summer, figure 9 and 3 moves to 8 and 4 in general clock. I cannot explain this structure. Watch this movie, please.
Thank you! That's right. It has double mainspring so that the torque of the mainspring is constant. Actually that torque is changing with how I wind it. Sorry, I'm Japanese and not good at English.