Boesenbergia rotunda — krachai (Thai), Chinese keys, fingerroot — a rhizome of the ginger family with a distinctive aromatic profile: a camphor-fresh, slightly medicinal, subtly floral note quite different from galangal or ginger. It is the defining aromatic of nam ya sauce (Entry TH-44) and jungle curry (Entry TH-37), and appears in certain steamed fish preparations. Its English names ('fingerroot' for its multi-fingered rhizome shape; 'Chinese keys' for the same reason) describe its distinctive appearance.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)