The first Tokyo Marathon was held on 18 February 2007. However, years prior to 2007, Tokyo Marathon actually consisted of two marathons -  the Tokyo International Marathon which took place on even years, and Tokyo - New York Friendship International Marathon which took place on odd years.
The first Tokyo Marathon was run on February 18, 2007. However, prior to 2007, the Tokyo Marathon consisted of two separate events - the Tokyo International Marathon held every even year and the Tokyo-New York Friendship International Marathon scheduled for odd-numbered years.