‘Devil’s tongue’is an alternative name for the konjak, or konnyaku tuber (Amorphophallus Konjack), which is a herbaceous perrenial and member of the yam family native to Indonesia. It was introduced into Japan in the sixth century, originally for medical use, but quickly became a standard part of the Japanese diet in the form of konnyaku. This is a gelatinous, grey speckled food, produced by peeling the tubers, boiling them and mashing them together with dissolved limestone – which causes the starch in the tubers to coagulate. The resultant food lacks taste but is used to provide a chewy texture to otherwise uninteresting dishes.