About 5 million people visit Hakodate in Hokkaido Prefecture, but in recent years this picturesque northern city has become known for another down-to-earth attraction: a hamburger restaurant that offers huge servings. Its unique hamburgers include fillings such as deep-fried chicken and crumbed pork cutlets. Many customers who come for a hearty lunch get so full that they do not need to eat dinner. Although Hakodate often tops surveys of attractive places to visit, the city also suffers from a falling population and high unemployment rate. For 3 days, we asked customers at this restaurant that has been loved by locals for decades about what they define as happiness