The names of Saturday and Sunday in Japan.

Sunday: Sun Yaori.

The sun, the moon and the fire are collectively called "obsidian", and the seven-star stone of the sun, the moon, the fire, the water, the wood, the gold and the earth are collectively called "seven obsidian". In ancient China, South Korea, Japan, and North Korea, it was customary to say that there were seven days in a week, such as "Japanese Obsidian Day" was Sunday, "Moon Obsidian Day" was Monday, and so on.

Extended data:

The origin of seven obsidians:

Zhou is called the Seven Obsidian in China. During the Xia, Shang and Zhou Dynasties in China, Seven Obsidian refers to the seven main stars, such as the sun, the moon and the five planets, which was an important part of astronomical astrology at that time. China's seven obsidians did not begin as a unit of time.

In the west, the ancient Babylonians first used seven days as a week. Later, the Jews spread it to ancient Egypt and from ancient Egypt to Rome. After the 3rd century AD, it spread widely to European countries.

As a time unit, waist-length was first established in the 7th century BC. Both Islam and Christianity hold religious worship activities on a weekly basis, so in many dialects, "worship" gradually has the meaning of "week".

The origin of the week should be the cycle connected with the moon, because seven days is about a quarter of the moon's week.

In ancient China, the ancients regarded the five planets of Sun, Moon, Jin Mu, Fire, Water and Earth as seven nights, which also made them the Seven Wonders. In the Preface of Biography of the Liang Dynasty by Fan Ning in the Eastern Jin Dynasty, there are seven records of "interference" among prostitutes.

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