Chinese yam (Dioscorea polystachya) — nagaimo or yamaimo in Japan, shānyào in China — is the long, pale, cylindrical tuber of an East-Asian climbing vine, and the one true yam widely eaten raw. Under a thin, fawn-brown, faintly hairy skin lies crisp, watery, ivory-white flesh that turns intensely slippery and mucilaginous the moment it is cut or grated. Peeled and grated raw it becomes tororo, a viscous, glossy purée slurped over rice or soba; cut into batons it stays snappy and clean- tasting. Its mild, faintly sweet, cucumber-fresh flavour and its slick texture set it apart from the dry, mealy tropical yam and from starchy purple ube.