This visual is the key visual of Tokyo Marathon 2017, which symbolizes its new course.
You'll be able to find this key visual posters at places like Tokyo Metro stations, sports retailers, etc.
http://www.marathon.tokyo/en/about/course/

[Design Concept]
In 2017, the Tokyo Marathon will have a new course, and the design concept of the poster visual is, "New Way, New Tokyo."
By presenting major changes of the new course with footprints of many different colors as key visual, it represents the new 42.195-km journeys of runners, as well as volunteers and spectators who support runners to complete their journey.