Japanese curry is like making beef stew but with a lot more flavor! All the spices are in the "roux"--a dry curry paste that looks like a chocolate bar so you don't have to buy a ton of seasonings! They are labeled mild, medium, or hot and commonly found at asian markets in boxes branded "S&B" or "House". A common Japanese dish eaten at home, this recipe is from the iron chef winner Katsuyo Kobayashi. It is published in her book, "the Quick and Easy Japanese Cookbook". You could also substitute the beef strips with chicken instead, both are quite good!