Ex-Formula 2 driver Tadasuke Makino set the pace in testing ahead of Super GT and DTM's joint racing at Fuji, as Audi's Loic Duval ran the Super GT field close.
Makino set the best time in the Nakajima Racing Honda-NSX GT, deposing Duval in the process, following a 10-minute red flag caused by Audi's Benoit Treluyer.
While the incident was not captured by live coverage, Treluyer's WRT Audi stopped facing the wrong way on the run to the fast Coca Cola left-hander.
When the session resumed in the final minutes, Makino set a 1m30.421s lap that stood as the best time, 0.227s clear of 2019 Super GT champion Kenta Yamashita in the #6 Lexus Team LeMans entry.
That left Duval in third, just over two tenths off the Lexus, as the Audi driver led the DTM field in both sessions, placing eighth in the morning's running and seven tenths off the leading pace.
The first session's benchmark was set by Ryo Hirakawa as the #37 TOMS Lexus driver demonstrated the experience of the DTM's Hankook tyres that he used at Hockenheim last month.
The DTM field endured a mixed session with 2019 champion Rene Rast and Audi stablemate Mike Rockenfeller both suffering punctures in the first practice session.
While Rast was eighth in the morning's running, he placed 11th in the afternoon.
BMW's Kamui Kobayashi and Alex Zanardi both got their first experience of a 2019-spec M4 DTM and could only place 16th and 22nd respectively in the morning.
Zanardi would remain last in the afternoon, with Kobayashi down in 19th ahead of Rockenfeller.
While the joint racing between the DTM and Super GT at Hockenheim ultimately did not use Balance of Performance, it is being considered at Fuji and Autosport understands its use will be continually reviewed during the weekend.
The threat of rain for both Saturday and Sunday's race would likely eliminate the need for BoP as it is expected to favour the DTM machines that have significantly less aerodynamics compared to the Super GT cars.
The testing period also included a practice Indianapolis-style restart for the DTM drivers to practice ahead of its use in the racing.
The Super GT teams are currently on track for their second tyre test of the Hankook compounds.