Walls which have the air of southern Europe
After arriving in Sotome, Father de Rotz came up with a new way of building walls. These walls have become known as “doro kabe” (“de Rotz walls”) and were made using stones from the local area. They have the air of southern Europe.
In Sotome, a type of metamorphic rock called crystalline schist (known locally as onjyaku) is found naturally. Traditionally, people in this area have used crystalline schist for the foundations of their houses, as well as to make kitchen stoves and to build walls around their houses. When building these walls, they formerly used a mix of red soil and straw.
This wasn't very suitable, however, because when it rained it would run out and easily break. When Father de Rotz arrived in Shitsu, he came up with a new idea for building walls. Instead of using this mixture, he dissolved red soil in water to form a muddy liquid before working in caustic lime and sand. He then used this mixture as an adhesive. Thanks to this, people were able to make walls which were robust. This way of building walls began to be used in many places across the local area, and this type of wall became known as a "de Rotz wall".
In places like Shitsu, “de Rotz walls” made using crystalline schist are numerous, but in the case of Ono church the “de Rotz wall” was made using basalt from Mt. Ono. It seems that Father de Rotz thought it good to use natural stones from the local area where possible. It is interesting to consider that the wall was made by a priest from abroad; it certainly has the air of southern Europe. The wall is so firm that after 130 years, it still remains standing today.