Highly recommended! They have a wide array of more than 20 standard Chinese dishes like gulaorou, jiachang doufu etc. The waitress immediately asked if we were vegetarian and if we could eat eggs, fish and so on. The vegetarian menu is in Chinese and Japanese, but the staff speak enough English to describe the dishes. But it really doesn't matter, they are all very good. About one third of the dishes are based on some kind of faux meat, but the "chicken pieces" we tried had a very hearty texture without any weird aftertaste. The rest is various kinds of tofu, veggies and fried things (spring roll, noodles...) There are only 2 or three dishes that contain egg, so make sure to confirm the ingredients with the staff if you are vegan.
The restaurant is not indicated on the Motomachi guide map, so it's a little tricky to find. It's located right next to one of the temples in Chinatown a short walk from the station. The Kanji are 長城饭店 (Great Wall Restaurant, chin. Changcheng fandian).
We had the Lazijiding ("Chicken" pieces with chili) and Mapodoufu (Spicy soft tofu). Both were really good, authentic Chinese food (not touristy stuff). The mapodoufu was a little unusual due to the addition of autumnal mushrooms, but tasty. Portions were normal and pricing moderate (700 - 1600 Yen).
Cons: not on Guide Map, not health oriented, no English menu