On his return to Japan he expressed embarrassment at having returned alive, rather than dying in the service of the emperor
Japan had changed utterly during his three-decade absence - some found his stoicism and loyalty inspiring, others found it absurd
He married in 1972, within months of his return and died in 1997, aged 82
He longed to meet Emperor Hirohito - in the end he was granted an audience with Emperor Akihito in 1991
Yokoi's long ordeal began in July 1944 when US forces stormed Guam as part of their offensive against the Japanese in the Pacific.
The fighting was fierce, casualties were high on both sides, but once the Japanese command was disrupted, soldiers such as Yokoi and others in his platoon were left to fend for themselves.
"From the outset they took enormous care not to be detected, erasing their footprints as they moved through the undergrowth," Hatashin said.
In the early years the Japanese soldiers, soon reduced to a few dozen in number, caught and killed local cattle to feed off.
But fearing detection from US patrols and later from local hunters, they gradually withdrew deeper into the jungle.
There they ate venomous toads, river eels and rats. Yokoi made a trap from wild reeds for catching eels. He also dug himself an underground shelter, supported by strong bamboo canes.
"He was an extremely resourceful man," Hatashin says.
Keeping himself busy also kept him from thinking too much about his predicament, or his family back home, his nephew said.
Return to Guam Yokoi's own memoirs of his time in hiding reveal his desperation not to give up hope, especially in the last eight years when he was totally alone - his last two surviving companions died in floods in 1964.
Turning his thoughts to his ageing mother back home, he at one point wrote: "It was pointless to cause my heart pain by dwelling on such things."
And of another occasion, when he was desperately sick in the jungle, he wrote: "No! I cannot die here. I cannot expose my corpse to the enemy. I must go back to my hole to die. I have so far managed to survive but all is coming to nothing now."
Two weeks after his discovery in the jungle, Yokoi returned home to Japan to a hero's welcome.
He was besieged by the media, interviewed on radio and television, and was regularly invited to speak at universities and in schools across the country.
Hatashin, who was six when Yokoi married his aunt, said that the former soldier never really settled back into life in modern Japan.
He was unimpressed by the country's rapid post-war economic development and once commented on seeing a new 10,000 yen bank note that the currency had now become "valueless".According to Hatashin, his uncle grew increasingly nostalgic about the past as he grew older, and before his death in 1997 he went back to Guam on several occasions with his wife.