Japanese/Korean Amynthas carnosus (Goto & Hatai, 1899) is redescribed from a newly designated Neotype (Tokyo NSMT An435). An annotated synonymy is presented that nominally includes: kyamikia Kobayashi, 1934, monstrifera Kobayashi, 1936, sangyeoli, youngtai, kimhaeiensis, sinsiensis and baemsagolensis - all Korean names by Hong & James, 2001, and Taiwanese monsoonus James et al., 2005. However, Chinese A. pingi (Stephenson 1925) (syn. fornicata Gates, 1935) is maintained separately, at least for the present, until its comprehensive review, possibly extending to DNA barcode differentiation.