Hagakure specializes in udon - messy but fun to slurp. After walking downstairs off of an Akasaka street, my friend and I were seated at a four person table later occupied by two more customers - pretty common in these small, traditional Japanese restaurants. Hagakure caters to the masses of businessmen who work in the nearby Prudential and TBS high rises and come streaming out in human ribbons during the lunch hour - interesting to see if you haven't worked in Japan before. Everyone's lunch hour is the same.
Hagakure's udon is good, but not great (for superb udon, go to Opippi in Kasumigaseki). The Japanese-only menu had about 8 simple menu items. I chose "take," which included a vegetable tempura and seaweed; my friend chose "niku," which means simply "meat." It turned out to be pork. There's not a whole lot of flavor - mostly whatever flavor comes from the tempura. I wasn't too enthused, but I have to admit that the restaurant seemed pretty popular that day.
Lunch is about 700 yen.