Anagumang was a (probably legendary) Yapese navigator who led an expedition in rafts and canoes five or six hundred years ago. On this expedition he discovered the islands of Palau, where he and his men first saw limestone. Limestone did not exist on Yap. The Palauan natives let the Yapese quarry this limestone in return for coconut meat, beads and copra; as well as performing services. Anagumang and his men first quarried the rock to make fish-shapes, but then changed to making the huge rings which are now known as Rai stones, which were easier to transport. These were then used as currency on Yap, despite being very hard to carry around. After this expedition, the Yapese frequently quarried more of these stones as more money was needed.
First Anagumang ordered his men to cut stone into the shape of fish, then a crescent moon, and then a full moon with a hole in it for transport.