The second and third legs of Super Formula qualifying at Motegi have been postponed until Sunday morning due to heavy showers.
Rain hit the track just before the start of qualifying, requiring all teams to switch to wet weather tyres.
Despite several drivers going off the track, including Andre Lotterer on his out lap, conditions were suitable enough for Q1 to be completed without any interruptions.
However, in the 10-minute interval until the start of Q2, conditions deteriorated quickly, forcing the organisers to shift the remainder of the qualifying to Sunday morning.
As per the new schedule, Q2 will begin at 9:20 am local time (+9:00 GMT).
Former European F3 race winner Nick Cassidy topped Q1 with a time of 1m39.764s, leading home Kondo Racing teammate Kenta Yamashita.
Kamui Kobayashi was next up in third, while Daisuke Nakajima and Red Bull junior Pierre Gasly completed the top five.
The wet conditions caught out several drivers, with former champions Yuji Kunimoto, Naoki Yamamoto and Hiroaki Ishiura all knocked out in the opening leg of qualifying.