Yamato-imo 大和芋, ‘mountain potato’, is a type of yam that has a wonderful culinary feature that is much prized in Japanese cuisine – when grated raw it produces a cloudy mucilaginous mound, which is very slimy, rather like the texture of raw eggs. Although ‘slimy’ conjures up something distasteful for people who do not have this texture featured in their cuisine, it is an important texture in Japanese cuisine and is found in that other much-commented on Japanese food: ‘natto’. The taste of yamato-imo is mild and so it is mixed with other ingredients mainly to produce this particular texture. The skin of the yamato-imo has a skin irritant in it and so it needs to be handled carefully and placed in a vinegar and water solution first before peeling. The flesh of the yam does not have this irritant but should still be placed in a vinegar solution to avoid any of the irritant remaining.