Georg Fritz (1865-1944), the German commander-in-chief of Saipan, wrote an extensive history and ethnography of the Chamorro ("Chamoru"), which was published in 1904 by the Royal Museum of Ethnology in Berlin. He described a game he called Tchonka that appears to be almost identical with Sungka, the predominant mancala variant played in the Philippines. The game also resembles Dakon on the island of Java and Ohvalhu in the Maldives. Chongka' was probably introduced by Filipino immigrants, which arrived on Guam in great numbers after 1722, when according to Robert F. Rogers the Spanish colonial government made a "proposal (...) to transport [them] to the Marianas for voluntary resettlement to revitalize the economy". Later the game became an integral part of Chamorro culture and identity.