Tsukuba Marathon begins at 10:30 am starting from the athletic field in the University of Tsukuba and first proceeding around the loop road within the university before spilling out on Higashi Odori and proceeding north. There is also a 10 km race that begins at 11:10, but that remains within the university.
The marathon course continues up Higashi Odori past the High Energy Accelerator Research Organization (KEK) and takes a left towards the Northern Industrial Park. After looping around that, the course then proceeds south along the Yatabe-Akeno Bypass until it comes to Tsuchiura-Gakuen Sen (called Expo Odori along this part of the road). From there, it proceeds back to downtown Tsukuba and turns north again on Nishi Odori, where it proceeds up past Hiratsuka Odori to the road with the overpass just north of the Tsukuba Memorial Hospital. From there is goes west back to the university loop and then back down and around into the athletic field where it ends.
Every year, hundreds of athletes vie for the winner's wreath, with the times ranging from around 2 and a half hours on up to 4 or more. With a little calculation, you can figure out just about when to expect the runners to go by. For instance, the lead runner should turn the corner onto Nishi Odori (just west of Seibu) at about 12:15.
Every year in November, unsuspecting drivers get caught in traffic jams caused when roads are closed temporarily to let the marathon runners by. So plan your trips accordingly.