Probably the most overused term in culinary matters in Japan is kodawari, which implies a strict scrupulousness, usually to flavor. Attendant to the idea of kodawari is simplicity: the more unprepossessing the food, the easier it is to appreciate its adherence to basic goodness. In this regard, the purest Japanese dish may indeed by sashimi, since it is simply sliced raw fish, but the purest prepared dish is sanuki udon.
Udon are wheat noodles, which are found everywhere in Japan. Sanuki udon is from the island of Shikoku. It is udon in a clear broth made from various stock ingredients such as mushrooms, bonito and seaweed. Sanuki udon is sustenance for common people, which means it has a reputation for being very cheap, but kodawari still applies. Outside of Shikoku, sanuki udon may be expensive in accordance with the unspoken rule that once a regional dish leaves its bailiwick it becomes something of a delicacy.
The udon chain Hanamaru blithely shatters this truism by offering sanuki udon at prices that are probably lower than they are in Shikoku. The most basic item on the menu is kake udon, which is merely noodles in broth topped with green onion. A small bowl will set you back a mere ¥105. A medium bowl is ¥210 and a large one ¥315.