Paul McCartney’s arrival at Tokyo’s Narita International Airport on January 16, 1980, marked his first visit to Japan since the Beatles tour of 1966. The occasion was a planned 11-city concert tour by his band Wings. Instead, Paul’s visit was limited to a nine-day stint in the Tokyo Narcotics Detention Center, which ended on this day in 1980.

McCartney was found to be carrying nearly half a pound of marijuana in his baggage upon arrival at Narita—an amount that Paul would later assure Japanese authorities was intended solely for his personal use. The amount was large enough, however, to warrant a smuggling charge and a potential seven-year prison sentence. Given Japan’s reputation for rigorous enforcement of its strict anti-drug laws, it was by no means a foregone conclusion that McCartney would escape trial and possible imprisonment, yet he was released and quickly deported from Japan on January 25, 1980, prior to making any appearance in court.

That a celebrity of McCartney’s stature would avoid the consequences that a less-famous drug smuggler might have faced was hardly surprising. After all, who could blame Japanese authorities for applying a double-standard to a prisoner whose sing-alongs inside the jailhouse and screaming fans outside threatened to create a significant distraction from the normal workings of the justice system? The question that troubled the minds of observers at the time was, “What was Paul thinking?” Half a pound of marijuana was a prodigious amount for one man to carry around for personal use—particularly a man who had had reason to expect especially close examination of his person and his baggage by Japanese customs officials. After all, Paul had been denied a Japanese entry visa just five years earlier due to his numerous earlier drug arrests in Europe.

Twenty years after his 1980 arrest, Paul would opine that his psychological motivation may have been to find an excuse to disband Wings, which he in fact did immediately following his return to England. In another interview, however, Sir Paul offered an explanation that may be the more compelling for its simplicity: “We were about to fly to Japan and I knew I wouldn’t be able to get anything to smoke over there,” McCartney said in 2004. “This stuff was too good to flush down the toilet, so I thought I’d take it with me.”