Level, 1 wins each over 2 singles meetings since 2025. Last meeting on 26/08/2026 at M25 Taipei.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 26/08/2026 | M25 Taipei | Round 1 | hard | Koyama | 6-7 6-1 5-2 |
| 02/09/2025 | M25 Sapporo | Round 1 | hard | Hazawa | 6-3 1-6 4-6 |
| hard | Hazawa 1 - 1 Koyama |
| 2026 | Hazawa 0 - 1 Koyama |
| 2025 | Hazawa 1 - 0 Koyama |
130 wins, 106 losses since 2021 (55.1%).
Last matches: D D D D V
38 wins, 40 losses since 2021 (48.7%).
Last matches: D V V V V
Level, 1 wins each over 2 singles meetings since 2025.
On 26/08/2026, at M25 Taipei (Round 1): Hiromasa Koyama won 6-7 6-1 5-2.