Taro's Blog

I forgot to tell my son about the days of the week in Japanese. It relates to the planets in the Solar System: Sunday = 日曜日, Monday = 月曜日, Tuesday = 火曜日, Wednesday = 水曜日, Thursday = 木曜日, Friday = 金曜日, and Saturday = 土曜日. In the English translation, Sunday = “Sun Day”, Monday = “Moon Day”, Tuesday = “Mars Day”, Wednesday = “Mercury Day”, Thursday = “Jupiter Day”, Friday = “Venus Day”, and Saturday = “Saturn Day”. (Sorry, Uranus and Neptune. You were reserve players.) Please read this article Names of the days of the week in Wikipedia, for further explanation.

Wait, there is something weird going on. OK, it’s no brainer that Sun = 日 (Sun), and Moon = 月 (Moon). However, why Mars =火星 (Fire Planet), Mercury = 水星 (Water Planet), Jupiter = 木星 (Wood Planet), Venus = 金星 (Metal Planet), and Saturn = 土星 (Earth Planet) in Japanese? The hint lies in the Wuxing (五行) philosophy of the ancient Chinese. The Buddhist monks (佛教僧侶) brought the knowledge of Wuxing (五行) from China to Japan like other things, such as Buddhism (佛教), Zen (禪), Vegetarianism (素食主義), Buddhist scriptures (佛經), Kanji (漢字), Paper (紙), Inksticks (墨), Incense sticks (香), Buddhist robes (佛袍), Tea (茶), Tofu (豆腐), Noodles (麵條), and the Architectural techniques of Buddhist temples (佛教寺廟的建築技術), etc.

Interestingly in the Chinese language, Sunday is 星期日 (Day Sun), Monday is 星期一 (Day 1), Tuesday is 星期二 (Day 2), Wednesday is 星期三 (Day 3), Thursday is 星期四 (Day 4), Friday is 星期五 (Day 5), and Saturday is 星期六 (Day 6).

Are 月曜日, …, and 土曜日 invented by the Japanese? Or did the ancient Chinese invent 星期月, …, 星期土 first, but they abandoned it? Some people discussed it in the Reddit forum. I do not know the answer yet.