This is a vintage Maru obi
with unique building, bridge and raft pattern, which is woven.
Textile has soft and glossy touch. (It seems to be silk and jinken (rayon) blend.)
The pattern is set upside down, and it's to be tied in 'hikinuki' style.
There is a whitish stain on maegara( front patterned part). (the 1st flaw photo)
It has discolorations on its base color, due to its old age.
There are other couple of flaws.
Please check detail photos.
Enjoy its distinctive fashion on vintage kimonos!
*Approx background color - near black dark brown