Not everyone knows that in Japan there are objects with megalithic masonry, where the blocks are of enormous size and weight. The first question is: what is it for?
We get the answer in the views of the imperial palaces. Under them there is a similar, but more primitive masonry. It's a kind of wall, fortification
The corners are laid out in the same way as in the first photo. But here, too, the polygonal masonry is primitive, the blocks are poorly fitted. Degradation of technology?
Remains of the retaining wall of the palace. High-quality polygonal masonry
But most striking is the wall next to Osaka Castle. This is clearly the filling of huge curved megalithic blocks. The layers in the monolith say about it.
Top blocks differ in color, probably cut and laid later
If it is not cast, then why cut, process and move such a huge block, when you can transport it in parts and add up the same volume?
Pay attention to the lower right corner - here the overlying rock did not completely hide the internal rubble stone or the lower masonry.
Is it also cast from geo-concrete?