Shou Sugi Ban 焼杉板 (or Yakisugi) is an ancient Japanese exterior siding technique that preserves wood by charring it. Traditionally, Sugi (cryptomeria japonica L.f., also called Japanese cedar) was used. The process involves charring the wood, cooling it, cleaning it, and finishing it with a natural oil. It is an environmentally friendly way to preserve the timber and (paradoxically) make it fire resistant. Chemical preservatives, paints, and retardants are thus unnecessary.