Hiroo Onoda surrendered in 1974, just over 28 years after the rest of his country, and nearly 30 years after he was first deployed to the Filipino island of Lubang. For that entire time, he waged a guerrilla war from the jungle against an imagined enemy: burning food supplies, destroying infrastructure, and trying to single-handedly prepare the island for a Japanese invasion that would never come. 30 years he harassed local villagers, 'requisitioned' food and supplies, and (though he neglects to mention this in the autobiography) killed civilians (up to 30, by some accounts).
The Japanese repeatedly attempted to contact Onoda and his 2 fellow soldiers (Corporal Shōichi Shimada and Private First Class Kinshichi Kozuka) but the men convinced themselves that each call to surrender was (albeit very convincing) enemy propaganda. Onoda's paranoia only grew over his years on Lubang, and it's difficult to say whether he would have ever come down had it not been for his chance meeting with explorer Norio Suzuki. As an aside, Suzuki was looking for "Lieutenant Onoda, a panda, and the Abominable Snowman, in that order," and later died in an avalanche looking for the Yeti. One can only assume he managed to find a panda.
Onoda's retelling of his '30-year war' is very matter-of-fact, very 'military.' As a result, his achievements felt understated, even though they are (even from a purely survivalist perspective) objectively incredible; almost unbelievable. Indeed, it is difficult to imagine Onoda being from any country other than Japan. His motivations appeared to be purely based on collectivist values - for the good of his country, at any cost. I'd hesitate to call Onoda a hero, but his honour and his tenacity are admirable. His behaviour upon returning to Japan appears to support this thesis: he turned down 30 years of back pay and eventually relocated to Brazil after experiencing disillusionment with modern Japan.
Onoda's story is at its most interesting, however, when he prolongs it. His rebuffs of letters, search parties, radio broadcasts, and the like become more paranoid as time goes on. One has to wonder whether, subconsciously, he didn't want the war to end. Onoda spent the bulk of his life fighting for a cause. 30 years gone, sacrificed in the name of the Japanese Empire. For this to be suddenly ripped away - to be revealed as a delusion - it's little wonder Onoda was doing everything he could to hold on to the story underpinning his reality, even as evidence grew to the contrary.