This particular recipe is based on one a friend in Osaka, Megumi Shimazu, taught me to make at her home many years ago. Yama-imo , also known as mountain yam, is a long root vegetable that has a sticky consistency when grated. While not absolutely necessary, it helps hold the pancake batter together. They also are not strictly necessary in this dish, but add a traditional flavor touch. If you can't find bottled tonkatsu sauce , you can substitute steak sauce or ketchup mixed with Worcestershire sauce to taste.
All unusual ingredients are available in Japanese markets.
Mix together yama-imo, flour, eggs, katsuobushi, and cabbage to form a stiff batter. Heat a lightly-oiled griddle. While cooking, top each pancake with a slice of pork. Turn pancake to brown both sides and cook pork thoroughly. Brush the pork with tonkatsu sauce.