When you travel, sometimes you are trying to take dance class where you visit.
I went to Japan last month and took a couple of Open Ballet classes in Tokyo. Hope this will help you when you look for the class in Tokyo.
Studio Architanz is Open class dance studio located in Tamachi.
The studio is in the office building, so it might be little bit hard to find it from outside of the building.
They have ballet classes for all level (Advanced, Intermediate and Beginner), contemporary, Pilates and so on. And the price is from 2,500 yen to 4,500 yen for one class.
If you are looking for the dance studio for the first time in Tokyo, definitely this is the place you should check it out first.