Sarashi

The character wears a sarashi.

A sarashi is a long strip of cloth, usually thick cotton, wrapped tightly around the midriff up to the chest. Historically worn under kimono both by samurai (to resist injury) and by women (for more "obvious" reasons, particularly in eras when a slim figure was considered fashionable), its association with warriors has made it a near-universal symbol of toughness in Japan.