There are two sets of courts. Come in the main gate from the station and go to the "main street" of the campus. Turning left and walking about 200 meters brings you to several courts that are for the students. Turning right, walking about 200 meters, making another right and wriggling between some buildings gets you to courts that are for faculty and staff.
For either set of courts, you need university connections. Based on my experience at Sophia University (see that listing), the students' courts are likely to be much harder to get use of. I used to live across the street from this campus, and the faculty/staff courts seemed much more open, especially before 9 or 10 AM on weekends. A few times I just walked on and used the courts.