Add a subrule to “Gold”, called “Burying”:-

A Chest is an object located at an Island, containing one or more Pieces, and having one or more Keepers. Chests are tracked as a list on [[The Golden Archipelago]] wiki page.

As a daily action, a Hunter may Bury Treasure by losing X Pieces (where X is at least 1): upon doing so, a Chest is created at their current location, containing X Pieces and with a list of Keepers chosen by the Hunter. (If any other Hunters share the Hunter’s location, the list must include all of those Hunters.)

As a daily action, a Hunter may Dig Up Treasure if they are located at an Island which has a Chest of which they are one of the Keepers: upon doing so, the Hunter gains a number of Pieces equal to those in the Chest, and the Chest is removed from play.