A type of vernacular house *minka 民家, characterized by one or more wings or ranges, known as *chūmon 中門, projecting at right angles from the basic straight range of the main house *omoya 主屋. The term is principally used in the north east of Honshū 本州 especially in Akita, Yamagata, Fukushima, and Niigata Prefectures, and derives from the resemblance to the *chūmonrō 中門廊, or central corridor of the *shoin 書院 style. Usually both the main range and the chūmonrō are thatched.
The functions and names of the projecting wings vary according to their position, and the style itself may be subdivided accordingly. Commonest and best known is the maya chūmon 厩中門, projecting from the front of the earth-floored area *doma 土間 at the lower *shimote 下手 end of the main range. Often with an entrance in the gable end, this wing usually contained a stable *umaya 馬屋, an entrance passage, and often a toilet and bath. It thus served as an enlarged porch to the earth-floored area, especially useful during the snowbound months of winter. The maya chūmon plan has a lot in common with the L-plan northern farmhouse *magariya 曲り屋, though the position of the entrance is somewhat different. Other types of chūmon include the *genkan chūmon 玄関中門, projecting from the front of the upper end *kamite 上手 of the main range, and incorporating a formal entrance porch for the reception suite, as well as an area for attendants *tomobeya 供部屋. Chūmon projecting from the rear of the main range are also found and include reception areas zashiki chūmon 座敷中門 and sleeping quarters nema chūmon 寝間中門 projecting from the upper end; and kitchen passages daidokoro chūmon 台所中門 or katte chūmon 勝手中門 at the lower end. Some houses might have more than one chūmon, giving rise to composite designs. Houses with a chūmon at each end of the facade, creating an inverted U-plan, were called ryōchūmon-zukuri 両中門造; those with a T-plan pairing zashiki and genkan chūmon or maya and katte chūmon were called kizuchi chūmon 木槌中門. Projections too small to be regarded as true chūmon are sometimes referred to as protruding navels debeso 出臍. The style was used for farmhouses in Akita Prefecture from the late 17th century, where it seems to have been associated initially with vernacular houses of the highest status. Its origins are not known, though connections with regions of heavy snowfall are strong. It is also clear from surviving plans that there were military-class residences buke yashiki 武家屋敷 with the chūmon-zukuri layout in the Tōhoku 東北 region in the 17th century.