Having contested his last race as a Honda driver, Sasahara appears close to completing his widely-anticipated switch to the Toyota camp for next year.
The 26-year-old made an appearance for TOM'S in the Super Formula post-season rookie test earlier this month in what was essentially an audition to replace Giuliano Alesi in the team's #36 car for next year.
Now he has logged his first miles at the wheel of the #37 Toyota GR Supra that he is expected to share with Alesi next season on the third and final day of a test involving the majority of the brand's GT500 cars at Motegi.
Last month, Toyota announced its GT500 driver line-ups for the 2023 SUPER GT season with the exception of the driver who will partner Alesi in what will become the Deloitte-sponsored #37 TOM'S entry.
TOM'S had both its #36 and #37 cars running at Motegi alongside fellow Bridgestone teams Rookie Racing, SARD and Cerumo, with only the Yokohama-shod Racing Project Bandoh car absent among the six-car Toyota stable.
It marks a change in approach for Toyota compared to last year, when it opted to spend the early part of the winter using only its test car as it trialled new aerodynamic solutions for the GR Supra, albeit with aero development now frozen for 2023.
GT500 rules permit only 24 hours of testing during the off-season (excluding official tests) per car, the equivalent of six days, but test cars are not subject to these limitations.
Sasahara is expected to be confirmed as a Toyota SUPER GT driver in January, although it remains to be seen whether he will get the nod to replace Alesi in the TOM'S Super Formula line-up alongside Ritomo Miyata.
TOM'S team manager Jun Yamada described Sasahara as "by far and away faster" than Alesi following the Suzuka test.
