Four of the six GR Supra teams took part in Saturday's running with a pair of small wings attached to the bonnet underneath the cooling ducts, with the presumed aim of increasing downforce.
The #36 and #37 TOM'S cars, the #14 Rookie Racing car and the #39 SARD car had the device equipped, while the remaining cars, the #19 Racing Project Bandoh and #38 Cerumo machines, did not.
It appears the device was not equipped on any of the six Toyotas for the previous pre-season test at Okayama (pictured below right).
Toyota's innovation comes against the backdrop of an aerodynamic freeze in the GT500 class, which has been implemented to save costs while a new generation of cars is developed for the 2024 season - creating some paddock debate about whether the new device will be deemed legal.
However, there appears to be a degree of ambiguity in the rules, which require the upper surface of the car to match its roadgoing counterpart except in areas marked by a so-called 'design line' that are open to development.
These include the area around the front and rear splitters, the 'flick boxes', wheel arches and side skirts.
Honda has also introduced a new bonnet aero solution for 2023, which was seen in the Okayama test as well as the Suzuka Fan Thanks Day event that took place the previous weekend.
It features a pair of sculpted underwings which taper inwards slightly towards the front bulkhead, which contrast to the straight strakes used for the 2022 model of the NSX-GT (pictured below).
All five Honda GT500 cars are using the same front bodywork design at Fuji.
Nissan has not modified the Z's bodywork in this area, sticking to the same design as was used in 2022.
