Namako wall or Namako-kabe is a special Japanese design widely used for vernacular buildings, particularly on fireproof storehouses in the latter half of the Edo Period. Typically, the namako wall is distinguished by a white grid pattern on charcoal gray slate. Namako kabe literally means "sea cucumber wall" and is a representative type of fireproof wall for traditional Japanese buildings. Namako wall timbers are wrapped with thick earthen layers and the surface is covered with charcoal gray square tiles whose joints are protected by thick white plaster. Therefore namako wall is strong against fire and well in insulation. The black and white diagonal design creates a special symmetry with the rest of the building. The naming of "namako" wall comes from the recognition that the shape of the joint plaster resembles a sea cucumber. As namako wall was expensive, only rich people could afford it and even those rich people gave priority to cover their kura storehouses with namako. In the center of the main settlement of Matsuzaki, Izu there are dozens of namako wall buildings.