Jenson Button was fastest again in the second practice session for the Japanese Grand Prix.
Three different cars occupied the top three places with Fernando Alonso second for Ferrari and Sebastian Vettel third for Red Bull.
Mark Webber was fourth fastest ahead of Felipe Massa and Michael Schumacher.
Schumacher was struggling with rear tyre grip towards the end of the session and had an off-track moment at the first corner.
Several incidents during the session made life difficult for drivers trying to set laps on the soft tyres.
One of the first drivers to go off was Bruno Senna, who lost control of his Renault at turn one.
He skidded across the tarmac run-off and into the gravel on the outside of the corner. Fortunately he kept the engine running and was able to continue.
Rubens Barrichello was not so lucky when he lost control of his car at the entry to Degner. He touched the grass on the way into the corner and spun into the barrier.
It was a double blow for Williams as Pastor Maldonado pulled over at the corner shortly afterwards with an apparently technical problem.
The most lurid moment of the session came when Kamui Kobayashi lost control of his car at 300kph going through 130R. Impressively he wrestled the Sauber away from the barrier at the inside of the corner and continued without damage.
Kobayashi had two other moments during the session, twice running wide at the Spoon Curve.
Vitantonio Liuzzi logged just four laps in his only practice session of the day before his HRT came to a stop.
2011 F1 season
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Image ?é?® Pirelli