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, 105 losses since 2021 (55.3%).
Last matches: D D D V V
33 wins, 39 losses since 2021 (45.8%).
Last matches: D V D 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.