Kami Kama-shiki and the Buddhist Hattan
In Chanoyu, when building the charcoal fire, sumi-bi, 炭火, the kama, 釜, kettle, is removed from the hearth, and placed on a folded pack of papers, kami kama-shiki, 紙釜敷, paper kettle-spread.
Left: an unfolded sheet of kami kama-shiki, 紙釜敷, paper kettle-rest, which is folded in half to two directions when used to temporarily support a kama, 釜, kettle, while building the charcoal fire in the hearth. The kami kama-shiki is based on the original kai-shi, 懐紙, heart-paper, kept in the front folding of the kimono. Right: paper facsimile of Buddhist ha-ttan, 鉢単, bowl-one, a meal placemat the is folded in thirds in both directions.
The Buddhist hattan is a black paperboard mat that is unfolded and used to arrange food bowls and utensils. The five nesting bowls are usually black. Perhaps it is no coincidence that the preferred bowl for Chanoyu is black. In its way, the charcoal in the fire for hot water is also a kind of offering, similar to the food that is also offerings.