What's with all the weird writing/symbols in the hot springs in 3rei?


In episode 5 of Prisma Illya 3rei, we find that Gil has somehow pulled an
entire hot springs out of the Gate of Babylon. The walls surrounding it have
banners with a number of strange symbols and quintessentially-Japanese words
on them.

You can see the symbols for yourself below; some of them are very strange,
like the biohazard symbol (☣), the radiation symbol (☢), and a pair of clubs
(♣) attached end-to-end. The words are "bonsai", "Mt. Fuji" ( _fuji-san_ ),
"sushi", "bushido", "[ _matsuri_](https://en.wikipedia.org/wiki/Matsuri)", "[
_kami_](https://en.wikipedia.org/wiki/Kami)", "sumo", "squid" ( _ika_ ), "[
_tenshukaku_](https://en.wikipedia.org/wiki/Tenshu)", and "heat haze" (
_kagerou_ ), plus one on the far-right in picture #1 that is cut off.

I have to imagine there is some sort of joke here I'm not getting. What is it?

> [![right
> wall](https://i.stack.imgur.com/4ggwGl.jpg)](https://i.stack.imgur.com/4ggwG.jpg)
> [![front
> wall](https://i.stack.imgur.com/P74o7l.jpg)](https://i.stack.imgur.com/P74o7.jpg)
> [![left
> wall](https://i.stack.imgur.com/LO9TBl.jpg)](https://i.stack.imgur.com/LO9TB.jpg)

(The images are spoilered because naked-but-steam-concealed characters.)




The banner looks similar to 武者幟 (warrior flag)

Around AD1600, There are civil war in Japan. In that time every warrior show
that flag to recognize each other.

[Wikipedia](https://en.wikipedia.org/wiki/Battle_of_Sekigahara) have some
picture of that war. ![Battle of
Sekigahara](https://upload.wikimedia.org/wikipedia/commons/9/9f/Sekigaharascreen.jpg)

Or [some city](http://www.kanko-sekigahara.jp/en/index.html) selling that flag
as goods. ![Flags](https://i.stack.imgur.com/3QHFT.jpg)

These flags have name of the 将軍 (General) or
[紋](https://en.wikipedia.org/wiki/Mon_\(emblem\))(the mark of the family).

In that ilier's case, it uses same format, but it doesn't use actual mark or
name. I think it shows "Gil's wrong Japanese stereotype".

