When floors are inserted into the roof space of minka so that the space can be utilised, whether for sericulture (as in the gasshо̄-zukuri framed minka discussed in previous posts) or some other purpose, the low, triangular edges of the space formed, where the roof plane meets the floor, are impractical for anything other than storage of relatively small items. To address this inefficiency, the transverse roof beams (koya-bari 小屋梁) can be set into the posts at a level significantly lower than the longitudinal wall beams (keta 桁), to give the attic storey walls; additionally, obstructive roof posts (tsuka 束) are omitted wherever possible, and may be entirely absent. These two characteristics are what define nobori-bari-gumi (登り梁組, lit. ‘rising beam framing’), which is the subject of this week’s post, the final entry in this ten-part series on minka roof framing methods.

In nobori-bari (登り梁) framing, the transverse roof beams are tenoned into the faces of the posts, while the nobori-bari sit on the heads of the posts, in an ori-oki (折置) configuration, in which the mortised beam ends are dropped onto vertical tenons on the post heads and the wall plates are lapped over the beams.

*Nobori-bari* framing in a board/plank-roofed *minka* in the Tо̄hoku region. This roof space was used for sericulture and other purposes.

Nobori-bari are functionally similar to the principal rafters (sasu 叉首) of sasu-gumi (叉首組) framing, but are true beams, being far stouter and usually made from irregularly shaped pine logs, minimally worked. They support the purlins (moya 母屋) on which the common rafters (taruki 棰 or 垂木) ride. At the apex, the nobori-bari may bear on a large longitudinal beam (ji-mune 地棟) which is supported by a central roof post (shin-zuka 真束) or muna-mochi-bashira 棟持柱). Again, like the sasu in sasu-gumi construction, the nobori-bari pairs are often crossed (with a tenoned, through-mortised and pegged joint) at the apex, forming a crotch in which the ridgepole (muna-gi 棟木) is carried. The moya may sit directly on the nobori-bari, or on very short posts or stumps (tsuka 束) to make up for height differences in the irregularly-shaped beams.

One interesting variation in nobori-bari framing is the use of brackets or ‘shelf’ timbers (makura-gi 枕木, lit. ‘pillow timber’) at the eaves. The lower end of the nobori-bari sits in the corner formed between the makura-gi and the post. The exterior part of the makura-gi may serve double duty as an ude-gi (腕木, lit. ‘arm timber’) to support the external ‘verandah’ beam (keta 桁); ideally, the loads acting at each end of the makura-gi on either side of the post balance each other out.