Koji Kobayashi leads a strong contingent of Japanese runners in this year's race.
He started this year with a personal best at the 2014 Tokyo Marathon, finishing ninth in 2:08:51. That gives him the eighth-fastest time in the field.
Kobayashi has some familiarity with the Chicago course, having run here in 2012.
Moving up to the next level in order to place against this field may be asking a bit much, but with competent countrymen Satoru Sasaki and Ryosuke Fukuyama also in the race, the Japanese could challenge and make things interesting.
"We've had a great relationship with the Japanese Federation," race director Carey Pinkowski said. "We're partners with the Tokyo Marathon and the Japanese record was set by a Japanese runner in Chicago, so Japanese athletes know it's a great place to run."