Gyoza!
This is absolutely a comfort food that you should try when visiting Japan. Gyoza (餃子) or Japanese dumpling is actually originated from China, but got really popular in Japan since the 20th century. This food is a labour of love wrapped with minced meat vegetables, soy sauce, sesame oil, and many other delicious ingredients. which then will be fried for a while to be able to give a unique, crunchy, flavourful taste (usually also called as yaki-gyoza). Some gyoza are only steamed and not fried, we call them sui-gyoza. Most restaurants and stalls sell 6-pieces set of gyoza for around 300 until 500 yen, which is a really great price for such food! The flavour will elevate once you dip the gyoza into a soy sauce.