Hi Salim,
Tokyo University has Department of Aeronautics and Astronautics which has 2 Masters program.
1. Master of Engineering in Aeronautics and Astronautics Specialisation in Aerospace Engineering
2. Master of Engineering in Aeronautics and Astronautics Specialisation in Aerospace Propulsion

The Department conducts an exam for their Masters intake. The exam is quite competitive. The annual intake for 2018 is 37.

For more information, please go through their official guide: http://www.aerospace.t.u-tokyo.ac.jp/education/resources/appguide2018eng.pdf