These stone walls are seen anywhere in a residential area.
This pattern is called Hishi.
It is like a square obliqued a little bit.
“Hishi” is said to be named after a water chestnut (Hishi in Japanese name), because the shape looks like its nut.
This pattern is also used for “Kamon” which is Japanese crest each family have from generation to generation.
This one in the photo is one big Hishi including four small Hishis.
In fact, this pattern was the crest of Shingen Takeda who was very famous general of Kai country, which is now Yamanashi prefecture, in the warring period (from 1493 to 1573).
So, this is also called Takeda Bishi.
The one in this photo is consisted of four squares looked like petals.
So, this is called Hana Bishi, that means a flower Hishi.
translated by Seiko