AMS 14C dating of wooden anchors and planks excavated from submerged wrecks located at Takashima in Imari Bay, Nagasaki Prefecture

According to folklore the fleet that was dispatched to Japan for the second Mongol invasion of 1281 encountered a fierce typhoon at Takashima. Radiocarbon (C-14) ages of wooden anchors and planks excavated from the submerged site at Takashima were determined using accelerator mass spectrometry (AMS). The C-14 ages are 745 +/- 20 BP for bamboo and 770 +/- 20 BP for wood from the intact wooden anchor, and 840 +/- 20/865 +/- 20 BP for the planks, respectively. The calibrated bamboo age of 1268-1284 cal AD and the slightly older age of 1257-1279 cal AD for wood suggest that the wooden anchor was manufactured just before the invasion. The age range of planks (1191-1236 and 1163-1215 cal AD) is consistent with an idea that they are likely to be derived from contemporaneous ships. The high-precision AMS C-14 dating confirms that the wooden anchors and planks are remains of wrecked Mongolian warships that were involved in the second Mongol invasion.