Rai stones are large circular disks with a hole in the center, like a doughnut, and stand as high as 12 feet tall and weighs as much as five tons each. Some of these stones are so large, they aren’t physically moved at all. They are simply owned, like immovable assets, and their transaction or ownership is recorded in the oral history. The physical location of the Rai is not important, the ownership is. In one instance, a large Rai was being transported by canoe when it accidentally dropped and sank to the sea floor. Although it was never seen again, everyone agreed that the Rai must still be there, so it continued to be transacted as genuine currency. When moving a Rai is necessary, a strong pole is passed through the hole and carried by men to the required destination. Smaller Rai stones measure 7-8 centimeters in diameter and are far easier to transact.
The limestone was originally carved from quarries in the island of Palau, located about 400 kilometers away. Limestone was nonexistent in Yap and therefore very valuable to the Yapese. The perceived value of a specific stone is based on its size and craftsmanship - the larger the stone, the higher its value. The amount of time and effort it took to transport the stone affected its value. At times, the men transporting the Rai stones would die during the journey. This loss of life increased the value of the stone depending on how many men were lost and for which particular Rai stone.
The trade for Rai stones eventually fell in disuse in the beginning of the 20th century due to trade disputes between Spanish and German interests in the area. When Imperial Japanese forces took over Yap during World War II, many stones were used for construction or as anchors.
Although modern currency has replaced the stones as everyday currency, the Rai stones are still exchanged in traditional ways between the Yapese, especially in rare important social transactions such as marriage, inheritance, political deals, or sign of an alliance.
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