The embellishment of gable pediments *tsuma 妻 by exposed structural members that were part of the overall system of roof construction when interior roof elements were open to the underside of the roof *keshō yaneura 化粧屋根裏. The term includes the ornamentation not dependent upon the structure that was applied to the gable pediments when ceilings, tenjō 天井, became common, and the hidden roof construction *noyane 野屋根 was erected over either the core of the building *moya 母屋, or over the entire structure, including the surrounding aisles *hisashi 廂. This change to the installation of ceilings occurred in the last decade of the 10th century.
Typical types of decorative effects in the gable pediment are: *inokosasu 豕扠首 (diagonal struts with center post); tateyokoshiki 竪横式 (a system of vertical and horizontal lattice placed at desired intervals); *kōryō kaerumata 虹梁蟇股 (a system of ornamentation with rainbow beams and frog-leg struts); *nijūkōryō kaerumata 二重虹梁蟇股 (a system of two rainbow beams and frog-leg struts); nijūkōryō taiheizuka 二重虹梁大瓶束 (a system of two rainbow beams with bottle struts); *kitsune gōshi 狐格子 (latticework).
From the Momoyama period to the end of the Edo period, the decoration in the gables, especially of hip-and-gable roofs *irimoya yane 入母屋屋根, was extremely complex. Gables were large, allowing a variety of decorative motifs to be combined with bracket complexes *tokyō 斗きょう, rainbow beams, frog-leg struts, and bottle struts.
