the pin or rivet holding the spines of a folding fan together / (by extension) a pivot, cornerstone, keystone / a pin, often decorated, holding the handle to the tang of a katana

(archaic, possibly obsolete) the pin or rivet holding the spines of a folding fan together

(archaic, possibly obsolete) fortress, redoubt / (archaic, possibly obsolete) important point, key

need, necessity / essential

a female given name

(gynaecology) menarche; first menstruation

chief of any place whose name ends in 所, such as an office or research facility

Numbers

real sword (as opposed to a wooden practice sword)

to lean against; to lean upon / to depend on; to rely on