The 2026 Japanese F4 Championship moved to Sportsland Sugo for Round 5, where changing weather conditions brought Ryo Shirasaki’s six-race winning streak to an end and produced two new Champion Class winners.
Shirasaki arrived after completing another sweep at Suzuka, having transformed a scoreless opening weekend into six consecutive victories and a 45-point championship advantage. However, Sugo delivered a very different challenge. Ryo Sakai mastered a drying track to claim his first victory in Race 9, before Soichiro Shioda converted pole into his own maiden win in a wet Race 10. Shirasaki still left the weekend with a larger championship lead after recovering to second on Sunday.
The Independent Class produced an even more decisive development. Hirobon followed his Suzuka victory with another perfect pair of wins at Sugo, taking Race 9 from pole before charging into the lead at the start of Race 10. Yutaka Toriba remained his closest championship rival entering the weekend, but his late retirement on Sunday allowed Hirobon to secure the 2026 Independent Class drivers’ title, while TEAM 5ZIGEN also wrapped up the teams’ crown.
Full results from Round 5 of the 2026 Japanese F4 season at Sugo
Shioda takes both Sugo poles
Dry conditions greeted the Champion Class for Friday qualifying despite intermittent drizzle earlier in the day. The session immediately became disrupted when a car stopped at Rainbow Corner on the opening timed lap, triggering the first Red Flag with 15 minutes remaining.
Once the session resumed, the order changed rapidly. Masaki Hamabe initially moved ahead before Shirasaki continued the momentum that had carried him through the previous three rounds. The Kageyama Racing driver recorded a 1:24.144 to lead, while Ryutaro Sakai and Yuta Suzuki also moved towards the front.
However, another interruption followed when Buntaro Igarashi crashed at SP Corner. Officials restarted qualifying with only four minutes remaining, leaving drivers with little time to prepare another attack.
Shioda made the opportunity count. The Bionic Jack Racing driver produced a 1:23.893 with a minute remaining, becoming the only driver to break into the 1:23s and securing his first Japanese F4 pole. Shirasaki finished 0.251s behind in second, with Hamabe third ahead of Ryutaro Sakai, Haruto Nakai and Yuta Suzuki.
Second-best laps determined the Race 10 grid, and Shioda again emerged on top. Shirasaki joined him on the front row, while Nakai secured third ahead of Hamabe, Ryo Sakai and Yuzuki Miura. Shioda therefore completed qualifying with a double pole as he searched for his first victory in the championship.
Japanese F4 Sugo Qualifying report
Sakai masters drying track to claim maiden Race 9 victory
Race 9 began in difficult conditions after light rain left sections of Sportsland Sugo wet. Teams faced an immediate strategic choice between slick and wet tyres, with the leading qualifiers largely favouring wets while several drivers further back gambled on a drying circuit.
Shioda retained the lead from Shirasaki through the opening corners, while Nakai moved into third. Hamabe, one of the drivers who had selected slicks near the front, immediately struggled for grip and spun at Turn 3, while further incidents added to a chaotic opening lap.
Initially, the wet tyres remained the stronger option. Shioda headed Shirasaki, Nakai and Ryutaro Sakai, while Ryo Sakai sat behind them on slicks. However, the track began improving quickly, and the balance of the race shifted with every lap.
By lap five, the slick runners had started setting significantly faster sector times. Ryo Sakai became the leading threat, rapidly reducing the gap to the cars ahead as the wet-tyre runners searched for damp sections to preserve their rubber.
The crossover became decisive around the middle of the race. Ryutaro Sakai moved past Shirasaki and Nakai as their wet tyres faded, but Ryo Sakai followed him through and then used the increasing grip from his slicks to attack the leaders.
On lap nine, Ryo Sakai first passed Ryutaro Sakai before catching Shioda and taking the lead. Meanwhile, Leon Ochiai produced an equally impressive charge on slicks, climbing through the field before passing Ryutaro Sakai for second on lap 11.
Kenta Kumagai also benefited from the tyre choice and moved into third by lap 13. Ochiai continued closing on the leader and set the fastest lap with a 1:25.769, but an incident involving Miura and Miki Onaga brought out the Safety Car before he could challenge for victory.
Officials could not restart the race before the chequered flag. Ryo Sakai therefore secured his first Japanese F4 victory, finishing ahead of Ochiai and Kumagai. Syo Momose completed a slick-tyre top four, while Ryutaro Sakai finished fifth as the highest-placed wet-tyre runner and Igarashi took sixth.
Japanese F4 Race 9 Champion Class report
Shioda converts pole into maiden Race 10 victory
Conditions became wetter for Race 10, removing the tyre gamble that had shaped Saturday’s contest. Every Champion Class driver started on rain tyres, while worsening conditions prompted officials to begin the race behind the Safety Car.
After two laps behind the Safety Car, racing began properly on lap four. Shioda controlled the restart and immediately started building a gap over Shirasaki, while Nakai remained third ahead of Hamabe and Ryo Sakai.
Ryo Sakai carried momentum from his Saturday victory and passed Hamabe for fourth at Turn 1 on lap five. However, Shioda had already begun establishing control at the front. With clear visibility ahead of him, he gradually pulled away from Shirasaki as spray made conditions increasingly difficult for the drivers behind.
By lap 10, Shioda had extended his advantage beyond five seconds and recorded the fastest lap of the race with a 1:33.950. Behind him, Shirasaki, Nakai and Ryo Sakai remained separated by only a few tenths at times, but none could create a clear overtaking opportunity.
Shioda eventually built his lead to almost nine seconds before Igarashi spun into the gravel at Turn 2 on lap 14. The stranded car prompted another Safety Car and erased the leader’s advantage, but recovery work continued until the final lap.
The race consequently ended under Safety Car conditions, allowing Shioda to complete a pole-to-win performance and secure his first Japanese F4 victory. Shirasaki finished second to recover valuable championship points after his scoreless Saturday race, while Nakai claimed third for his second podium of the season.
Ryo Sakai followed in fourth after his Race 9 victory, with Hamabe fifth and Miura sixth. Although Shirasaki’s winning streak ended at six races, his Sunday result ensured that he still strengthened his overall championship position at Sugo.
Japanese F4 Race 10 Champion Class report
Shirasaki extends Champion Class lead despite end of winning streak
Shirasaki entered Sugo with 150 points and a 45-point advantage over Masana Muto. Although his six-race winning streak ended on Saturday, second place in Race 10 added 18 points and moved him onto 168.
The battle behind him changed considerably. Ryo Sakai’s victory and fourth-place finish lifted him to 108 points and promoted him from third to second in the championship. Muto failed to add to his Suzuka total and consequently slipped to third on 105 points.
Igarashi remains fourth with 76 points, while Kumagai’s Race 9 podium helped him climb to fifth on 63. Hamabe follows only one point behind on 62, ahead of Momose on 56 and Ryutaro Sakai on 55. Shioda’s maiden victory moved him to 48 points and ninth, while Miura completes the top 10 with 46.
The Teams’ Championship also changed hands at Sugo. TGR-DC Racing School moved from three points behind HYDRANGEA Kageyama Racing after Suzuka to a 16-point advantage, taking the lead with 192 points against Kageyama Racing’s 176. OTG MOTOR SPORTS sits third on 63, ahead of HFDP with B-Max Racing Team on 58 and MITSUSADA RACING on 55.
2026 Japanese F4 standings after Round 5 at Sugo: Champion Class
Drivers’ standings
- Ryo Shirasaki – 168 points
- Ryo Sakai – 108 points
- Masana Muto – 105 points
- Buntaro Igarashi – 76 points
- Kenta Kumagai – 63 points
- Masaki Hamabe – 62 points
- Syo Momose – 56 points
- Ryutaro Sakai – 55 points
- Soichiro Shioda – 48 points
- Yuzuki Miura – 46 points
Teams’ standings
- TGR-DC Racing School – 192 points
- HYDRANGEA Kageyama Racing – 176 points
- OTG MOTOR SPORTS – 63 points
- HFDP with B-Max Racing Team – 58 points
- MITSUSADA RACING – 55 points
- Bionic Jack Racing – 48 points
- B-MAX ENGINEERING – 36 points
- AKILAND RACING – 33 points
- PONOS RACING – 31 points
- Eagle Sports – 18 points
Full 2026 Japanese F4 standings
Hirobon and Kentaro split Independent Class poles
The Independent Class followed the Champion Class onto a dry circuit for qualifying, although the session produced an exceptionally close fight at the front.
Hirobon established himself among the leaders early before Yutaka Toriba, Shoichiro Akamatsu and Kentaro all challenged for pole. With the field continuing to improve, Hirobon eventually recorded a 1:25.286 to move back to the top.
Akamatsu came within only 0.001s of beating him, while Kentaro finished third after setting a 1:25.323. Toriba qualified fourth ahead of Makio Saito and William.
However, Hirobon’s session ended dramatically when he left the circuit and hit the barrier between Turns 3 and 4. Officials showed the Red Flag with two minutes remaining and did not restart qualifying, leaving his earlier benchmark intact.
Second-best laps produced a different order for Race 10. Kentaro secured pole ahead of Hirobon, while Toriba took third. Akamatsu, William and Saito completed the top six, setting up another close championship battle between Hirobon and Toriba.
Hirobon controls wet Race 9 for fifth victory
Light rain created a difficult start to Race 9, but unlike the Champion Class race that followed, the Independent field unanimously chose wet tyres.
Hirobon retained the lead from pole, with Akamatsu holding second and Kentaro initially third. Toriba immediately began applying pressure and completed a move on Kentaro at Turn 1 on lap two, bringing himself into the fight behind the leading pair.
As the race settled, Hirobon gradually created breathing room at the front. Akamatsu and Toriba continued contesting second, while Kentaro struggled to match the pace of the top three. Further back, Ikari produced an impressive opening lap from the rear of the grid and climbed rapidly through the field.
Hirobon had built an advantage of approximately two seconds when William crashed at Turn 3 on lap eight, prompting the Safety Car and erasing the gap.
Racing resumed on lap 12, and Hirobon judged the restart well enough to maintain first. The more significant change came immediately behind him when Akamatsu ran wide at Turn 1. Toriba seized the opportunity at Turn 2 and moved into second.
Hirobon remained clear of the battle behind and rebuilt enough of an advantage to win by approximately 1.5 seconds. Toriba finished second to limit the championship damage, while Akamatsu completed the podium.
Kentaro held fourth ahead of Ikari and Saito, but another 25 points moved Hirobon significantly closer to wrapping up the championship on Sunday.
Japanese F4 Race 9 Independent Class report
Hirobon wins again to secure Independent Class title
Race 10 began on a semi-wet circuit as light drizzle continued to fall. Most drivers initially arrived on the grid with slick tyres before increasing rain prompted almost the entire field to switch to wets. Only Ikari committed to slicks from the rear.
Kentaro started from pole, but his launch immediately opened the door for Hirobon. The championship leader accelerated cleanly from second and swept into first before Turn 1, while Kentaro recovered well enough to retain second.
Toriba remained close behind and soon began pressuring Kentaro as Hirobon gradually increased his advantage. Akamatsu initially joined the fight but started to fall back, leaving Kentaro and Toriba separated by only a few tenths.
Hirobon stretched his lead towards two seconds before Kazuhiro Kanayama spun into the gravel at Horseback Corner on lap 10. Officials deployed the Safety Car, once again eliminating the leader’s advantage and giving Toriba another opportunity to attack Kentaro.
The race restarted on lap 15 with Hirobon still ahead. Toriba then launched an attack on Kentaro into Turn 1 on the following lap, but he approached from too far back and lost control on the inside. His car spun onto the outer kerb and became stranded, ending his race and his championship challenge.
Officials deployed another Safety Car to recover Toriba’s car, and the race ended without another restart. Hirobon crossed the line first for his sixth victory of the season, while Kentaro finished second and Akamatsu completed the podium. William took fourth ahead of Masayoshi Oyama and Saito.
More importantly, Toriba’s retirement gave Hirobon enough of an advantage to secure the Independent Class championship at Sugo. TEAM 5ZIGEN simultaneously claimed the teams’ title, completing a decisive weekend for both driver and team.
Japanese F4 Race 10 Independent Class report
Hirobon seals Independent Class crown at Sugo
Hirobon arrived at Round 5 with 151 points and a 52-point advantage over Toriba. Two more victories added the maximum 50 points and moved the TEAM 5ZIGEN driver onto 201.
Toriba’s second place in Race 9 moved him onto 117, but his Race 10 retirement left him there. Kentaro’s fourth and second-place results lifted him to 111 points and brought him to within six of Toriba in the fight for second.
Nobuhiro Imada remains fourth on 81 points, while Oyama moves to fifth with 74. Dragon follows on 68 ahead of Akamatsu on 60, while Ikari sits eighth with 57. Saito has 44 points and Isao Nakashima completes the top 10 on 42.
TEAM 5ZIGEN also leaves Sugo with an unassailable advantage in the Independent Teams’ Championship on 201 points. HYDRANGEA Kageyama Racing sits second on 117, narrowly ahead of B-MAX ENGINEERING on 115 and Field Motorsport on 111. AKILAND RACING completes the top five with 94 points.
2026 Japanese F4 standings after Round 5 at Sugo: Independent Class
Drivers’ standings
- Hirobon – 201 points
- Yutaka Toriba – 117 points
- Kentaro – 111 points
- Nobuhiro Imada – 81 points
- Masayoshi Oyama – 74 points
- Dragon – 68 points
- Shoichiro Akamatsu – 60 points
- Ikari – 57 points
- Makio Saito – 44 points
- Isao Nakashima – 42 points
Teams’ standings
- TEAM 5ZIGEN – 201 points
- HYDRANGEA Kageyama Racing – 117 points
- B-MAX ENGINEERING – 115 points
- Field Motorsport – 111 points
- AKILAND RACING – 94 points
- Rn-sports – 81 points
- Eagle Sports – 60 points
- Bionic Jack Racing – 57 points
- HELM MOTORSPORTS – 36 points
- ZAP SPEED – 30 points
Full 2026 Japanese F4 standings
Shirasaki retains control as Hirobon wraps up title
Round 5 brought an abrupt end to Shirasaki’s remarkable run of six consecutive Champion Class victories, but the championship leader still emerged from Sugo in a stronger overall position.
Ryo Sakai’s maiden victory transformed the fight behind him, moving the TGR-DC Racing School driver into second on 108 points. However, Shirasaki now holds a 60-point advantage with four Champion Class races remaining, while Muto sits a further three points behind Sakai.
The Teams’ Championship remains more competitive. TGR-DC Racing School has moved into first on 192 points, but Kageyama Racing remains within 16 points after Shirasaki’s second-place finish in Race 10.
Meanwhile, Hirobon leaves Sugo with the Independent Class title already secured after completing a double victory. His six wins across the opening 10 races have also delivered the teams’ championship to TEAM 5ZIGEN, leaving the remaining rounds to determine the positions behind the new champion.
Japanese F4 now heads to Autopolis for Round 6 from 15-18 October, where Shirasaki will look to return to winning form while Ryo Sakai and Muto continue their fight for second in the Champion Class standings.
