Japan, the second palace.

this is a courtyard located in the outskirts of the city. It covers an extremely wide area. It doesn't have the strong sense of mixing steel and soil from the high-rise buildings in the city center. There are wooden works everywhere. So From the outside, it is a wooden building, a building made of pure wood.

but these are all superficial phenomena. If you look carefully, you can see that the walls here are generally about three inches thicker than ordinary walls.

this is a large courtyard. It looks like it's made of wood. Actually, it's a complete steel monster.

the three inch thick steel plate...