Tales of discoverings about Japan

Recently I found out that:

1. until the year 400 a.c. Japanese was just a spoken language;
2. Japan is made of 3500 islands
3. 75 % of it's surface is covered by mountains, of which 265 are volcanoes and 20 of these volcanoes are still active
4. 16% of the surface is covered by fields.

The numbers are stunning. This means that 120 million people live on less than 9 % of Japan's surface. (approximately 31.500 square meters)

Yesterday I learned the kanjis for the days of the week. It was surprising to find out that the symbols for the days of the week have the same 'element' as the ones in all the other languages that I know. For example the name for Monday is guetsuyo:bi. where the kanji guetsu means moon (yobi means 'day of the week') ; and it goes the same for all the other days.

What I find again surprisingly is that even if they have a totally different culture and a totally different alphabet, a different religion they still have the same symbols for the days of the week as the rest of us. I wonder where does it come from. After all they did not have the Roman and Greek gods. Either an anthropologist can give me the appropriate answer, either they named their days of the week differently before the Portuguese influence.

Stunned and happy that I can finally read the banners of Toyota and Honda. :)