Folded noshi
熨斗 noshi

A long hexagonal paper fold holding a strip of dried abalone; attached to gifts as a token of good fortune and long life.
Muromachi-period samurai gift etiquette; abalone offering custom
A noshi is a folded paper decoration that originally wrapped a strip of dried, stretched abalone (noshi-awabi), a food offering that stood for long life. The Ogasawara and Ise schools set rules for attaching noshi to gifts at feasts and weddings, and a 1731 Sukenobu print shows one. Over time the abalone was replaced by a strip of yellow paper, and noshi became a small printed symbol.
Printed noshi on gift paper (noshigami) mark celebratory gifts today; they are left off condolence gifts and gifts of fish or meat.