| Canada Open Qual | 2023/07/04 16:55 | Kai Schaefer v Parupalli Kashyap | L | 0-2 |
| European Games | 2023/06/28 08:30 | Luka Wraber v Kai Schaefer | W | 1-2 |
| Thailand Open Qual | 2023/05/30 06:55 | Chia Hao Lee v Kai Schaefer | L | 2-1 |
| Malaysia Masters Qual | 2023/05/23 02:00 | Christian Adinata v Kai Schaefer | L | 2-0 |
| Sudirman Cup | 2023/05/15 02:20 | Kunlavut Vitidsarn v Kai Schaefer | L | 2-0 |
| Orleans Masters | 2023/04/05 12:40 | Lanxi Lei v Kai Schaefer | L | 2-0 |
| Spain Masters Qual | 2023/03/28 08:40 | Christian Adinata v Kai Schaefer | L | 2-0 |
| Polish Open | 2023/03/25 10:00 | Julien Carraggi v Kai Schaefer | L | 2-1 |
| US Open Qual | 2023/07/11 19:00 | Koo Takahashi v Parupalli Kashyap | - | home |
| US Open Qual | 2023/07/11 16:15 | Koo Takahashi v Jhuo-Fu Liao | W | 2-0 |
| Thailand Int. | 2023/03/08 08:10 | Yu Jen Chi v Koo Takahashi | L | 2-0 |
| Thailand Int. | 2023/03/07 10:40 | Koo Takahashi v Chong King Lim | W | 2-0 |
| Estonian Int. | 2023/01/13 17:30 | Koo Takahashi v Joran Kweekel | L | 1-2 |
| Estonian Int. | 2023/01/13 09:10 | Christian Faust Kjaer v Koo Takahashi | W | 0-2 |
| Irish Open | 2022/11/17 12:20 | Koo Takahashi v Lucas Claerbout | L | 0-2 |
| Irish Open Qual | 2022/11/16 18:55 | Koo Takahashi v Valentin Singer | W | 2-0 |