Before Beatlemania, there was the distinctive Höfner violin bass — the primary guitar that Paul McCartney purchased after turning into the bassist for the Beatles.

That bass might be heard on among the band’s most well-known hits, together with “Love Me Do,” “She Loves You,” and “Twist and Shout.”

Mr. McCartney picked up the instrument in a Hamburg music retailer in 1961, and it accompanied the Fab Four as they rocketed to beautiful success, turning into probably the most well-known band on this planet. But the guitar vanished eight years later.

A brand new marketing campaign is searching for to search out the lacking instrument, and a whole bunch of individuals have responded, hoping to assist resolve the decades-old thriller: Where is Paul McCartney’s lacking bass guitar?

“It’s a hugely significant instrument in its own right,” stated Nick Wass, a semiretired advisor for Höfner, the guitar’s producer, who has joined forces with two journalists to try to monitor the guitar down. “It’s the bass that made the Beatles.”

“The bass was absolutely at the heart of the origins of the Beatles sound,” stated one of many journalists, Scott Jones, who labored for the BBC. “The smallest pieces of information can often lead to the biggest breakthroughs,” he stated of their attraction for recommendations on its destiny.

Mr. Jones’s spouse, Naomi, is the opposite journalist behind what they’re calling The Lost Bass Project.

The three Beatles followers have urged members of the general public to come forward with any info that may assist. No tip is just too small, they are saying, and they’re promising to maintain sources confidential. They say they’ve already obtained a number of credible leads for the reason that undertaking was launched on Saturday.

The instrument’s treasured place in Beatles mythology is intertwined with the band’s story. After the departure of their unique bassist, Stuart Sutcliffe, Mr. McCartney, who had been taking part in guitar, switched devices to exchange him throughout a residency in Hamburg in 1961. For that, he wanted a brand new bass guitar.

“I got my Violin Bass at the Steinway shop in the town center. I remember going along and there was this bass which was quite cheap,” he stated in a 1993 interview with Guitar Magazine, including that he had not wished to enter debt and will solely afford the Höfner, 500/1 guitar on the time. It value about £30 kilos, or $38, he recalled. “And once I bought it, I fell in love with it.”

Mr. McCartney took the guitar again to Britain, the place it accompanied the Beatles by a whole bunch of gigs — from the band’s early live shows on the Cavern Club in Liverpool, the place they had been noticed by Brian Epstein, who would turn into their supervisor, to the recording of their first two albums. It was repaired in 1964, in keeping with the workforce behind the brand new search, after which used together with different bass guitars.

But the last confirmed sighting of the instrument was in London in 1969, in video footage of the band members writing their ultimate album, “Let It Be.” Rumors have percolated ever since about what occurred to the instrument: The Lost Bass Project means that it might have been stolen or misplaced both from the basement of Abbey Road Studios, or from the Apple Corps recording studio on Savile Row.

A consultant for Paul McCartney declined a request for an interview. But Mr. Wass stated he understood, from earlier communications with Mr. McCartney, that he was eager to be reunited with the instrument. “He calls it the ancient one,” Mr. Wass stated.

Among the leads they’d obtained, Mr. Jones stated, had been recommendations that the instrument might have traveled to the United States or Japan. But he added that every one the leads must be vetted. “Somewhere among that information there is going to be the answer,” he stated.

Other iconic devices have been misplaced and located through the years — one shut instance being a Gibson acoustic guitar belonging to John Lennon, which was purchased in 1962 after which misplaced the next yr. Half a century later, it re-emerged and was offered at public sale in 2015 to an nameless purchaser for $2.4 million.

It is unclear what the market worth of Mr. McCartney’s lacking guitar can be, however the workforce behind the search insists that the hassle is just not for financial achieve, calling the guitar “priceless.”

“We just want to know where it is,” stated Mr. Wass.