A gate with a gable roof constructed with two square or rectangular main posts and two square or circular secondary posts *hikae-bashira 控柱, set to the rear. A heavy, horizontal beam *kabuki 冠木, is set into boat-shaped brackets *funahijiki 舟肘木, also called *mebari 女梁, and runs transversely on top of the main posts. Other beams *obari 男梁 are placed on top of the boat-shaped brackets and fit over the kabuki by means of cogged joints *watariago 渡腮. These beams extend toward the inner side wall beyond the main posts, and their ends are supported by the secondary posts. They fill the role of a bracket *udegi 腕木. The eave purlins *gagyō 丸桁 are supported by these extended transverse beams. The ridge is not set directly above the main pillars and the heavy, horizontal beam. Instead, struts, *tsuka 束, are placed at the center of the obari and other diagonal struts, *sasuzuka 扠首束, are attached to them. Bearing blocks *masu 斗 are positioned on top of these struts to carry the ridge *munagi 棟木. The center struts may vary in shape: dry squid shape, surumezuka 鯣束; bottle-shaped struts *taiheizuka 太瓶束; plectrum-shaped struts *minozuka 蓑束; or wooden frog-leg struts itakaerumata 板蟇股 (see *kaerumata 蟇股). The secondary posts are secured to the main posts by straight, short members which extend through the main pillars and through the secondary pillars. They are tighten by wedges *kusabi 楔. The upper member is called hikaenuki 控貫, the lower one is called ashimoto hikaenuki 足本控貫. The roof is generally gabled *kirizuma yane 切妻屋根, but on very rare occasions, it is a hip-and-gabled *irimoya yane 入母屋屋根 style.
Originally, the gate had no doors but extant examples have them. The use of this type of gate dates back to the late 14th or early 15th century. According to the Teikin ōrai 庭訓往来, the gate was used by doctors and patients and considered lower in rank than the *munamon 棟門. By the Edo period, yakuimon were used as gates for samurai 侍 dwellings and on a larger scale, 3 bays wide, for the mansions of noblemen. They were also used for castles. Examples include: Ten'onji Sanmon 天恩寺山門 (mid-17th century) in Aichi Prefecture, a 1-bay yakuimon with gable roof covered with finely layered shingles *kokerabuki 柿葺; and Kōdaiji Omotemon 高台寺表門 (1610) in Kyoto, a 3-bay yakuimon, with gable roof covered with tile *hongawarabuki 本瓦葺.
Ten'onji Sanmon 天恩寺山門 (Aichi)