The main convenience store we would go to in Japan was Family Mart because we had one that was just a 5 minute walk away from our apartment. They have some of the best prepared food choices there. That's actually a common thing in Japan convenience stores, including 7-Eleven, Lawsons, etc. In this haul, I ended up buying sushi, butter and syrup filled pancakes, and a coffee tapioca drink. My other half got a spaghetti dish, sandwich, and a strawberry milk. This was only the beginning of many food hauls in one of Japan's convenience stores.
I highly recommend trying out Japan convenience stores' prepared meals as they are affordable yet delicious.
♥ Love, Chris