| ITF W15 Sapporo | 07/23 02:30 | 25 | Asahi Kosaka v Mio Mushika | 4-6,1-6 | |
| UTR Pro Takasaki Women | 09/10 02:09 | - | Honoka Uchiyama v Kosaka Asahi | 4-6,2-6 | |
| UTR Pro Takasaki Women | 09/09 01:15 | - | Natsumi Nakadate v Kosaka Asahi | 1-6,5-7 | |
| UTR Pro Takasaki Women | 09/07 00:45 | - | Aya Ishii v Kosaka Asahi | 6-1,6-2 | |
| UTR Pro Takasaki Women | 09/06 00:00 | - | Ai Yamaguchi v Kosaka Asahi | 6-3,6-1 | |
| UTR Pro Noda Women | 08/27 04:45 | - | Noelani Teso v Asahi Kosaka | 6-3,6-1 | |
| UTR Pro Noda Women | 08/25 01:30 | - | Asahi Kosaka v Hinata Chiba | 6-4,5-7,2-6 | |
| UTR Pro Noda Women | 08/22 00:30 | - | Uta Asakura v Asahi Kosaka | 6-1,5-1 |