nhk world's risa wakabayashi explains. >> reporter: at the airport in hokkaido, the gateway to japan's far north. many airport stores sell fresh seafood to travelers, but there's one store that's attracting customers with a sales system called sumekodai, which means all you can stuff into a container. six kinds of organic cherry tomatoes are sold by the cupful. customers try to stuff as many tomatoes as possible. >> translator: i didn't know there are so many different types. i'd like to try them all. >> reporter: we visited farmer hiroki otsuka to see how the produce is grown. he and his wife grow 22 kinds of organic vegetables, including cherry tomatoes, eggplant, italian parsley on 18 hectares of fields. his farm earns $1 million in annual sales. only about 1% of hokkaido vegetable farmers make this much. the reason for otsuka's success is his motto -- never to sell products in the same way as other farmers. one of his popular products is dried sweet potatoes that are selling extremely well. thanks to his unique way of marketing them. usually we don't see many varieties of dried swe