@Kyujyu : in France, it is a traditional product and mustard is super spicy, you usually have only "strong" and "extra-strong" spicyness. You can have honeyed ones in the speciality stores, but that's pretty rare. The flavor is as strong or stronger than wasabi, with a longer lasting effect.
And iI like that each one of them get a mustard-filled one. Well-played, Chii
Mustard aside, I was just thinking about how in Japanese restaurants in America (at least, every one I've ever gone to), gyoza is always an appetizer. And yet in Japan, it is the main dish.