Japanese castle walls, Uchikomihagi

Important elements of the Japanese castle's defensive systems, the curtain walls were built by using several different methods, classified today according to the stone work or by the way the wall was raised. Interestingly, sometimes even for a single castle multiple techniques were used...

In this photo you can see the most common construction technique, called Uchikomihagi, used for an external wall at the Osaka Castle: rocks of different sizes were piled-up and smaller stones were pounded to fill-in the gaps.