Tokyo Marathon 2013 is held every year since 2007 in February. This year it is scheduled for February 24th. Since they are a day ahead of us, it is being held right now! Here is the course map:
As you can see the route takes you to all major sight seeing spots in Tokyo, and here are the description:
The maximum number of entrants are 35,500 people and you must submit an application first. It usually exceeds the maximum number so they usually do a lottery. And those lucky people who are chosen to run at the marathon have to pay 10,000yen (12,000yen if you’re from overseas). If you are interested for the next Tokyo Marathon 2014, application period is around August so don’t miss out!
You will get to see runners in costumes: