Held as part of the popular Suzuka Fan Thanks Day event, the one-hour session represented the first chance for the series' regular drivers to sample the revised Dallara-built machine they will race this season.
Running with the SF23, which features a revised aerodynamic package designed to reduce downforce and promote better racing, had up to now been limited to Super Formula's pair of development cars.
But the full 22-car field was in action on Saturday, with each team also revealing their new machines in full livery for the first time.
The fastest time of the session was set by Hiroki Otsu, standing in for Dandelion Racing rookie Kakunoshin Ota after the latter's crash during SUPER GT manufacturer testing on Friday.
Otsu's best time was a 1m37.003s, precisely one second slower than Tomoki Nojiri's pole lap in the final round of the 2022 season at the same track with the previous-generation SF19 car.
Second-fastest was Ritomo Miyata for TOM'S on a 1m37.078s, followed by Kamui Kobayashi for KCMG on a 1m37.099.
Toshiki Oyu, whose place on the Super Formula grid was only finally confirmed on Friday by the rebranded TGM Grand Prix squad, set the seventh-fastest time, one place ahead of defending champion Nojiri.
Red Bull junior Liam Lawson was ninth-fastest, fractionally slower than his Mugen team-mate Nojiri.
Ukyo Sasahara was 11th for Kondo Racing, where he is replacing Kenta Yamashita for both the Fan Thanks Day and the two-day official pre-season test that begins on Monday.
Sasahara was the only driver in the field to have driven the SF23 prior, having taken part in the series' most recent in-house test session at Motegi last month.
B-Max Racing's Nobuharu Matsushita appeared to suffer mechanical issues and did not set a time, while his team-mate Raoul Hyman caused a red flag when he came to a stop at the hairpin.
There is a further free practice session planned for Sunday morning at Suzuka, with a presentation of the 22 drivers that will contest this year's championship as well as demo runs planned for the afternoon.
Pre-season testing is set to kick off in earnest with a pair of two-hour sessions on Monday, with two more following on Tuesday.
Super Formula shakedown results:
| Pos. | No. | Driver | Car | Time |
|---|---|---|---|---|
| 1 | 6 | Hiroki Otsu | DOCOMO DANDELION M6Y SF23 | 1'37.003 |
| 2 | 37 | Ritomo Miyata | VANTELIN TOM'S SF23 | 1'37.078 |
| 3 | 7 | Kamui Kobayashi | Kids com KCMG Cayman SF23 | 1'37.099 |
| 4 | 38 | Sho Tsuboi | P. MU/CERUMO･INGING SF23 | 1'37.347 |
| 5 | 18 | Yuji Kunimoto | Kids com KCMG Elyse SF23 | 1'37.421 |
| 6 | 65 | Ren Sato | TCS NAKAJIMA RACING SF23 | 1'37.449 |
| 7 | 53 | Toshiki Oyu | TGM Grand Prix SF23 | 1'37.465 |
| 8 | 1 | Tomoki Nojiri | Red Bull MOTUL MUGEN SF23 | 1'37.476 |
| 9 | 15 | Liam Lawson | Red Bull MOTUL MUGEN SF23 | 1'37.513 |
| 10 | 36 | Giuliano Alesi | VANTELIN TOM'S SF23 | 1'37.566 |
| 11 | 3 | Ukyo Sasahara | REALIZE Corporation KONDO SF23 | 1'37.656 |
| 12 | 64 | Naoki Yamamoto | TCS NAKAJIMA RACING SF23 | 1'37.797 |
| 13 | 14 | Kazuya Oshima | docomo business ROOKIE SF23 | 1'37.851 |
| 14 | 39 | Sena Sakaguchi | P. MU/CERUMO･INGING SF23 | 1'37.871 |
| 15 | 20 | Ryo Hirakawa | ITOCHU ENEX TEAM IMPUL SF23 | 1'37.993 |
| 16 | 19 | Yuhi Sekiguchi | ITOCHU ENEX TEAM IMPUL SF23 | 1'38.041 |
| 17 | 12 | Nirei Fukuzumi | ThreeBond Drago CORSE SF23 | 1'38.131 |
| 18 | 4 | Kazuto Kotaka | REALIZE Corporation kONDO SF23 | 1'38.471 |
| 19 | 5 | Tadasuke Makino | DOCOMO DANDELION M5S SF23 | 1'38.613 |
| 20 | 55 | Cem Bolukbasi | TGM Grand Prix SF23 | 1'39.658 |
| 21 | 51 | Raoul Hyman | BYOUBUGAURA B-MAX SF23 | 1'40.247 |
| 50 | Nobuharu Matsushita | BYOUBUGAURA B-MAX SF23 | no time |
