obi stiffener; obi board
A thin, stiff board or piece of fabric inserted inside the obi (kimono sash) to keep it smooth and give it a crisp shape. Common in traditional Japanese dress.
When wearing a kimono, inserting an obi board makes the obi look neat.
batten plate; stay plate
Technical term in engineering or construction for a metal plate used to reinforce or connect structural members. Not related to kimono.
In this steel frame structure, the stay plates firmly connect the columns and beams.
Compound of 帯 (obi, 'sash') and 板 (ita, 'board'). The engineering sense is a semantic extension based on the shape and function of a flat plate.