Two-time Grand Slam winner Garbine Muguruza was among those who practiced Wednesday in Tokyo.
German Jan-Lennard Struff trained with countryman Philipp Kohlschreiber.
The Olympic flag flies above the Ariake Tennis Park.
World No. 1 Novak Djokovic enjoyed his first day back in the Japanese capital, where he triumphed in 2019.
Dayana Yastremska looks over during her team's practice session Wednesday.