I was studying some Japanese this morning and I rather embarrassingly forgot some days of the week. So I decided to turn my attention to those instead since it's such an obvious thing to know. Whilst revising I also practised writing the kanji for them as they are pretty basic and useful to know. It is actually fairly interesting in that the first kanji for each day of the week has an elemental meaning, as seen below:

It's more fun to remember the days by thinking "Hmm what day is it? Oh, it' FIRE DAY" but the similarity to our western calendar got me thinking. We have continued to use the "seven planets" that the Ancient Greeks and then the Romans used. These being the seven visible planets from the Earth (Sun, Moon, Jupiter, Saturn, Venus, Mars and Mercury). Sunday and Monday remain obvious whilst Saturday is named after Saturn. The Romans Gods were named in turn after these planets but Saturn was the only deity adopted by the Anglo-Saxons who instead replaced the rest of the days with their own deities of similar attributes. I just so happen to know what they replaced them with:

Damn Germanic tribes messing up the lovely Romaness of it all.

Although now it is easier to see the connection to the gods and therefore the seven classical planets. So this got me thinking about the structure of the Japanese week. Surely it is no coincidence that a completely different culture on the other side of the world just so happens to have seven days. On top of that, they have corresponding days named after the Sun and Moon and the rest of the days have a corresponding attribute like those of the Roman gods. My first thought was that the Japanese may have adopted the seven day week when they first came into contact with the Portuguese in the 16th century. Possibly accepting the Sun/Moon and choosing to up their own meanings for the rest of the days. They kind of hated the Portuguese though and it just didn't seem to make sense. Then I thought briefly about when the Americans came in 1854 and forced Japan to open up to the West but that didn't seem 100% right either.

After this I started to wonder how the seven day week came into such common use. It's such a simple question that I've never really thought about. Well, I did a little research and it isn't that difficult after all. It appears that the classical seven planets were recognised by ancient astronomers in Mesopotamia and Egypt and over the centuries spread across the world. It was first adopted by those in the Middle East and Ancient Greece. It was then adopted by the Romans in the 1st century and somehow made its way to China by the 4th century. The Chinese elements were then attributed to the days and subsequently picked up by the Japanese when they stole... ahem borrowed lots of Chinese culture in the early 9th century. The Chinese planet names largely died out and when modern Western influence came about they introduced a new system. The Japanese system on the other hand was not widely used but when they were pressured into harmonising their working calendars with those of the West in the late 19th century... it was ready to be picked up and used. To this day the first five planets in Chinese/Japanese are still named after the elements like 'Fire Star' and 'Water Star' just as we use the Roman gods.

History is awesome.