Face à face
| Japon - T League | 2020/12/15 08:00 | Mizutani, Jun v Koki Niwa | L | 1-3 |
| Hong Kong Open (WT) 2019, Singles | 2019/06/07 11:10 | Koki Niwa v Mizutani, Jun | W | 2-4 |
Home History
| Japon - T League | 2020/12/22 11:00 | Yukiya Uda v Mizutani, Jun | W | 2-3 |
| Japon - T League | 2020/12/17 04:30 | Mizutani, Jun v Yoshimura, Kazuhiro | W | 3-1 |
| Japon - T League | 2020/12/15 08:00 | Mizutani, Jun v Koki Niwa | L | 1-3 |
| Japon - T League | 2020/12/11 05:30 | Panagiotis Gionis v Mizutani, Jun | L | 3-2 |
| Japon - T League | 2020/12/05 03:30 | Mizutani, Jun v Taimu Arinobu | W | 3-1 |
| Qatar Open 2020, MS, Qualification | 2020/03/06 16:50 | Jingkun Liang v Mizutani, Jun | L | 4-3 |
| Qatar Open 2020, MS, Qualification | 2020/03/05 15:10 | Robert Gardos v Mizutani, Jun | W | 1-4 |
| Japon - T League | 2020/02/09 04:00 | Mizutani, Jun v Takuya Jin | L | 2-3 |
Away History
| Japon - T League | 2020/12/22 06:30 | Panagiotis Gionis v Koki Niwa | W | 2-3 |
| Japon - T League | 2020/12/20 09:30 | Koki Niwa v Kenta Matsudaira | L | 2-3 |
| Japon - T League | 2020/12/16 07:30 | Koki Niwa v Shunsuke Togami | L | 0-3 |
| Japon - T League | 2020/12/15 08:00 | Mizutani, Jun v Koki Niwa | W | 1-3 |
| Japon - T League | 2020/12/11 01:00 | Koki Niwa v Shunsuke Togami | L | 0-3 |
| Japon - T League | 2020/12/10 04:30 | Hiroto Shinozuka v Koki Niwa | W | 1-3 |
| ITTF Finals | 2020/11/20 04:30 | Gaoyuan Lin v Koki Niwa | L | 4-0 |
| Coupe du monde | 2020/11/14 05:15 | Koki Niwa v Woojin Jang | L | 3-4 |