On June 12, 1965, Shigematsu set a world's best in the marathon with a time of 2:12:00 at the Polytechnic Marathon. Less than two months earlier, he had set a course record at the 1965 Boston Marathon (2:16:33). In his career, in 22 marathons started, he recorded 6 victories, placed second 3 times and third once. Shigematsu ran seven marathons under 2:20.
- All results regarding marathon, unless stated otherwise
|1964||Fukuoka Marathon||Fukuoka, Japan||5th||2:17:57|
|1965||Beppu Ōita Marathon||Beppu, Ōita Japan||4th||2:16:15|
|Boston Marathon||Boston, United States||1st||2:16:33|
|Polytechnic Marathon||Chiswick, United Kingdom||1st||2:12:00|
|1966||Beppu Ōita Marathon||Beppu, Ōita, Japan||9th||2:16:16|
|1968||Beppu Ōita Marathon||Beppu, Ōita, Japan||10th||2:17:46|
|Lake Biwa Marathon||Ōtsu, Japan||4th||2:17:15|
- On 40th anniversary of first sub-2:09, pioneering Clayton looks back on his Marathon World records . IAAF (2009-05-30). Retrieved on 2015-01-23.
- 1965 article from The Times
- Boston Marathon History Archived 2017-10-03 at the Wayback Machine. Boston Marathon. Retrieved on 2015-01-23.