Great Britain's Heather Watson was knocked out in the first round of the women's singles as she went down in straight sets to Anna-Lena Friedsam.
The German took a tight opening set on a tie-break and broke twice in the second to win 7-6 (7-5) 6-3 in one hour and 49 minutes.
Andy Murray and Joe Salisbury are now on court against French pair Pierre-Hugues Herbert and Nicolas Mahut.
Jamie Murray and Neal Skupski will also feature later at Ariake Tennis Park.
The British pair take on Argentina's Andres Molteni and Horacio Zeballos in the men's doubles.