Hendrick Conrad Joannes Heusken (January 20, 1832 – January 15, 1861) was a Dutch-American interpreter for the first American consulate in Japan, established at Gyokusen-ji in Shimoda, Shizuoka in the late Bakumatsu period.[1] He played an important role in the negotiations for the "Harris Treaty" which opened commercial relations between Japan and America, and his assassination caused a minor diplomatic crisis between Japan and the various Western powers. [2]