Jacopo Prisco , CNN Written by

This is an update post- auction on September 9th.

A one-off Ferrari Daytona sold for €1.8 million ($2.17 million) over the weekend, as part of one of the largest ever Ferrari auctions. The sale was not only notable for the bids it attracted but because, until recently, many thought the car didn't even exist. Ferrari had, in fact, only ever commissioned one street version of its Daytona with a full aluminum body.

But for the last 40 years, this one-off was nowhere to be found. That's because it was gathering dust in a Japanese barn after being shipped out of Italy in 1971.

'A significant find'

Between 1969 and 1973, Ferrari produced over 1,200 units of its 365 GTB/4, a two-seat grand tourer capable of 174 mph and unofficially nicknamed "Daytona." It also commissioned five lightweight alloy versions of the car, to compete in the endurance race 24 Hours of Daytona. And just one alloy version that was street legal.

This is that very car, bearing the chassis number 12653 and featuring an all-aluminum body by renowned car designer Sergio Scaglietti, whose "Carrozzeria" has been doing chassis and body assembly on Ferrari cars since the 1950s.

The Daytona's interior. Credit: courtesy RM Sotheby's

"This is reportedly the only alloy-bodied, non-racing 365 GTB/4 built," Jared Zaugg, a classic car expert and a consultant on classic car auctions said in an email.

"The alloy body offers weight reduction, which helps to improve performance. Add to that the state of original, time-capsule preservation and you have a very special car. This is a significant find."

Also among the features are Plexiglas headlamps, black leather interiors and power windows.

Big in Japan

Completed in 1969, the car was exported to a Japanese dealership in 1971 and then featured in the January 1972 issue of Car Graphic, a Japanese motoring magazine. After passing hands several times, it ended up in the barn of its last owner, Makoto Takai, some time around 1980.

The story bears striking resemblance to that of another Daytona -- though one made by Shelby, not Ferrari -- which was hidden away for 30 years and then unearthed in 2001.

Auction results

The car was sold unrestored and in "barn find" condition, with just over 22,000 miles on the odometer. But the Daytona was not the most expensive car to sell at the weekend RM Sotheby's auction, which was held at the marque's own factory in Marenello, Italy.