Toshiro Sakai has found clay courts difficult, recording 22–28 across 50 matches (44.0%). The numbers point to a surface that has not consistently suited the game — a key area of opportunity on the calendar. Toshiro Sakai has reached 1 final without yet claiming a title on clay — one of the finest margins in tennis.

At Grand Slam level (Roland Garros): Toshiro Sakai is 3–4 (42.9%) across 7 Grand Slam matches — below .500, though the elite draw depth at the Slams makes that a notoriously difficult barrier to crack.

One final reached on clay, without converting it into a title. That final-round experience is valuable groundwork for going one step further next time. 2 semifinals. 2 quarterfinals.

By format on clay — best-of-five: 5–9 (35.7%); best-of-three: 17–19 (47.2%). Markedly stronger in three-set formats; the win rate drops noticeably in five-setters, which has direct implications for Grand Slam performance on clay.

Best season: 1971 — 4–4 (50.0%) from 8 matches. The best single-season display to date — a useful reference point as the clay record continues to develop.