A board which is inserted between the host's mat *temaedatami 点前畳 and the guest mat in a tea room *chashitsu 茶室. Its purpose is to add a little extra space to two- or three-mat tea ceremony rooms. The width of the board is about 32.4 cm, the same as the firebox, and its length equals the width of the mat. The thickness of the board is about 4.51 cm. If the firebox is not placed on the host's mat but outside *dero 出炉, for example, a small mat *daimegiri 台目切, may ever be set into the middle board. Red pine and zelkova are two of the types of wood used. It is said by some that Sen Sōtan 宗旦 (1578-1659), a grandson of Sen Rikyū 千利休 (1522-91), first used the naka-ita at a certain Yamada 山田 tea ceremony house in front of Daitokuji 大徳寺, Kyoto. However others attribute its creation to Joshinsai 如心斎 (ca. 1705-51). Examples: Kanden'an 菅田庵 in Shimane Prefecture and Hanshōan 半床庵 belonging to the Hisada 久田 line of tea masters in Kyoto.