Our official app, Tokyo Marathon App, offers you the "Spectator Navigator" feature that allows you to check where runners are expected to be at on a map, and the "Runner Update Service" that allows you to check your 5 km split time.
These tracking features requires you to enter the Number Card information or name of the runners you're looking for.
*Searchable results are unofficial and provided for reference only.
Both services are available from around 9:00 am on the race day.
Click here for more details on the Tokyo Marathon App.