Head-to-Head
Overview
Hiromasa Koyama and A. Arcon have met 1 time so far, all in 2026. Hiromasa Koyama leads 1–0. Their first encounter was at the 2026 M15 Harmon (R32), won by Hiromasa Koyama.
By surface
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Hiromasa Koyama and A. Arcon have met 1 time so far, all in 2026. Hiromasa Koyama leads 1–0. Their first encounter was at the 2026 M15 Harmon (R32), won by Hiromasa Koyama.