This so-called boat or canoe money is of bronze, unlike tiger tongue money, the silver ingots in the same currency area. Tiger tongues were issued from the 16th to the 18th century in Lan Chang, a kingdom on the Mekong River in the border area between present-day Laos and eastern Thailand. In 1707, Lan Chang split into diverse kingdoms which adopted the traditional currency. The succession state Luang Prabang additionally introduced such bronze boat ingots in 1707.