Tokyo Jogging Routes
I love running around the Jingu-Gaien Loop (1.3 km) that circles around the Meiji Memorial Picture Gallery, baseball fields, and soccer fields. The loop is wide enough that it never becomes too crowded.
I also really enjoy running through Yoyogi Park. The park is large enough that you can run on several different paths, and there are always activities there to entertain you (people practicing musical instruments, dance/cheer practices).