Satoimo (里芋) or taro roots are small and have hairy brown skin. You have to peel the skin before cooking. It gets slimy as soon as you start peeling, so be careful. They are often prepared through simmering in dashi and soy sauce.
Since taro roots are enjoyed in many of Asian cuisine, so you can find them at Chinese, Korean, Japanese groceries stores.
Recipes Using Satoimo (Taro)