Overview of the Japanese Days of the Week
The Japanese days of the week are:
- 日曜日 (nichiyōbi) – Sunday
- 月曜日 (getsuyōbi) – Monday
- 火曜日 (kayōbi) – Tuesday
- 水曜日 (suiyōbi) – Wednesday
- 木曜日 (mokuyōbi) – Thursday
- 金曜日 (kin’yōbi) – Friday
- 土曜日 (doyōbi) – Saturday
The suffix 曜日 (yōbi) means “day of the week.” The first character in each word provides the key to the day’s origin.
Astrological and Elemental Roots
The Japanese system for naming days is derived from the ancient Chinese tradition of the Seven Luminaries (日月火水木金土), which correspond to the five classical elements and two celestial bodies. This tradition, in turn, was influenced by Greco-Roman astrology, which associated each day with a planet or celestial body. The names were imported into Japan along with Buddhism and other aspects of Chinese culture during the 6th and 7th centuries.
Breakdown of Each Day’s Origin
Sunday – 日曜日 (nichiyōbi)
日 (nichi) means “sun,” reflecting the association of this day with the Sun. This is similar to the English “Sunday.” The concept comes from the ancient belief that the Sun governs this day.
Monday – 月曜日 (getsuyōbi)
月 (getsu or tsuki) means “moon.” Like the English “Monday,” it is named after the Moon, which was believed to influence this day.
Tuesday – 火曜日 (kayōbi)
火 (ka) means “fire.” In the Chinese Five Elements (Wu Xing), fire is one of the fundamental elements. The association with Mars, the “fire star” (火星, kasei), led to this day being named for fire, paralleling English “Tuesday,” which is named for the Norse god Tiw, associated with Mars.
Wednesday – 水曜日 (suiyōbi)
水 (sui or mizu) means “water.” This day is linked to the planet Mercury, called the “water star” (水星, suisei) in East Asia, following the elemental system.
Thursday – 木曜日 (mokuyōbi)
木 (moku or ki) means “wood.” The day is associated with Jupiter, known as the “wood star” (木星, mokusei) in Chinese and Japanese tradition.
Friday – 金曜日 (kin’yōbi)
金 (kin) means “gold” or “metal.” This links to Venus, the “metal star” (金星, kinsei), reflecting the Five Elements philosophy.
Saturday – 土曜日 (doyōbi)
土 (do or tsuchi) means “earth.” Saturday is associated with Saturn, the “earth star” (土星, dosei) in East Asian cosmology.
The Influence of Chinese and Western Traditions
While the elemental and planetary naming system originated in China, its roots go back further to Greco-Roman astrology, which was transmitted through translations and cultural exchange along the Silk Road. When the system arrived in Japan, it was adapted to fit the local language and writing system, thus creating the familiar names Japanese learners study today.
Interestingly, this system is not unique to Japanese. Korean and Vietnamese, which also drew from Chinese linguistic and cultural heritage, use similar naming conventions for their days of the week.
Learning Tip: Mnemonics and Cultural Connections
For Japanese learners, connecting the kanji for each day with its elemental or celestial meaning can be a powerful mnemonic tool. For example, remembering that 火 (fire) refers to both Mars and Tuesday helps cement vocabulary and kanji recognition. Talkpal’s AI-powered language tools can further support your learning with interactive exercises and cultural notes tailored to these origins.
Conclusion
The names of the Japanese days of the week offer a window into the country’s linguistic history and the broader cultural exchanges that shaped East Asia. By understanding their origins—from ancient Chinese cosmology to planetary deities—you gain not only a memorization aid but a deeper appreciation for how language and culture intertwine. As you continue your Japanese studies with resources like the Talkpal AI language learning blog, keep exploring these connections to enhance your fluency and cultural knowledge.
