Toshiro Sakai has found grass courts difficult, recording 14–18 across 32 matches (43.8%). The numbers point to a surface that has not consistently suited the game — a key area of opportunity on the calendar.

At Grand Slam level (Wimbledon): Toshiro Sakai is 7–8 (46.7%) across 15 Grand Slam matches — below .500, though the elite draw depth at the Slams makes that a notoriously difficult barrier to crack.

By format on grass — best-of-five: 11–11 (50.0%); best-of-three: 3–7 (30.0%). Significantly better in five-set matches — a strong physical profile on grass that tends to tell as matches and tournaments progress.

Best season: 1973 — 3–2 (60.0%) from 5 matches. The best single-season display to date — a useful reference point as the grass record continues to develop.