Kenta Yamashita and Kazuya Oshima endured a year to forget in 2023 as they wound up seventh in the standings with just a single top-three finish to their name, which came when the disqualification of the #23 NISMO Nissan in the August Suzuka race promoted them to third.
What made their difficulties even more puzzling is that Sho Tsuboi and Ritomo Miyata assembled a dominant campaign at the wheel of their #36 TOM'S Toyota GR Supra, winning three times (a feat not managed since 2011) and taking the title by a solid margin.
Rookie was usually the second-best of the Toyotas, only failing to score points all year, but it never really looked liked ever challenging for a win, much less the title. The wet Okayama opener was the only track where Yamashita and Oshima finished as the top GR Supra crew.
And while TOM'S certainly had an off year in 2022, not helped by Toyota's driver line-up decision making, the fact it so effortlessly beat the squad that looked in a strong position to supplant it as the unofficial 'factory' Toyota team has to ring alarm bells.
"We’ve always won at least one race in the last two years, but this year we weren’t able even get on the podium," lamented Yamashita speaking to Motorsport.com. "So it was a season that made me feel like we lacked something."
Without doubt, the GR Supra ended 2022 as the weakest of three GT500 machines, lagging behind the all-new Nissan Z and updated Honda NSX-GT Type S. With aerodynamics still frozen for 2023, there was little reason to expect much change.
Yamashita believes that the introduction of carbon-neutral fuel might have helped matters in terms of engine performance, but thinks that the title-winning TOM'S crew's ability to always move forwards in the race was the real key to the team's success.
He highlighted the example of the penultimate round at Autopolis, where Tsuboi and Miyata won from 12th on the grid on sheer pace alone while the Rookie car slipped from fourth to sixth.
"I have the impression that the Supra is still inferior to the NSX and the Z in general," said Yamashita. "I feel like the difference in power got smaller from last year, but especially compared to the Z, we are still losing out in the medium- and high-speed corners.
"But even then the #36 car was able to win the championship. The main difference between us and them was race pace.
"We were not so different in terms of qualifying, if anything I’d say we were stronger. But for example at Autopolis, we started fourth and dropped down in the race, while the #36 came from almost last to win. We just weren’t good enough in terms of race pace."
Earlier in the year, Oshima suggested that TOM'S having Miyata participate in the April tyre test at Suzuka was a major advantage in terms of allowing the #36 crew to choose the right tyres for Round 3, where Tsuboi and Miyata almost won with 40kg of success ballast.
In the champions' press conference, Tsuboi himself also mentioned the September Motegi test as a reason for the team's strength in the season finale at the same track.
Asked whether he felt tyre selection was the pivotal factor, Yamashita opined that it was one of several areas where TOM'S had an edge.
"I think tyre selection was a factor," he said. "But if I look back on the year, there were times that we were on the same tyre, and I don’t have the impression that the #36 was doing anything amazing with the set-up.
"That said, it feels like that the #36 was always able to improve its positions. The drivers are quick, they were good in the pitstops, and they were just strong as a total package. By contrast, the #14 was lacking in many areas."
Hopes of a first podium of the season on merit in the Motegi season finale for Yamashita and Oshima were dashed when Oshima was turned around in a battle for position by the Kunimitsu Honda of Iori Kimura.
A slow puncture for the Rookie car forced Oshima to trail back to the pits, leading to the team having to make a second pitstop, but despite that he and Yamashita were still able to finish as high as sixth.
Oshima told Motorsport.com that set-up changes to the #14 machine were responsible for the turnaround, and may provide Rookie with a direction to pursue in a bid to regain competitiveness next year.
