Head-to-Head
Overview
Hikaru Shiraishi and Hiromasa Koyama have met 1 time so far, all in 2026. Hiromasa Koyama leads 1–0. Their first encounter was at the 2026 M15 Karuizawa (QF), won by Hiromasa Koyama.
By surface
- clay0 – 1
Hikaru Shiraishi and Hiromasa Koyama have met 1 time so far, all in 2026. Hiromasa Koyama leads 1–0. Their first encounter was at the 2026 M15 Karuizawa (QF), won by Hiromasa Koyama.