A drenched circuit on Friday afternoon meant that Suzuka fell quiet during the second 90 minute practice session.
Steady and often heavy rain sent rivers of water flowing in the downhill pitlane, leaving the drivers not willing to risk their cars in the puddles or use up their limited supply of rain tyres.
"It's tough because we don't have enough tyres," confirmed McLaren's Heikki Kovalainen, according to British radio BBC.
"If we had more, I'm sure everyone would go out, but everyone is concerned it might rain tomorrow and Sunday -- although the forecast doesn't suggest that," the Finn added.
Qualifying should be dry on Saturday afternoon, but the morning practice session may also be wet.
"It would be very exciting to go into qualifying with your first very dry laps. You would have to guess your set up a bit," said Nick Heidfeld.