Throughout the entire "Journey to the West", the most mysterious thing is immortality. In order to live forever, the monsters rushed to extend their claws to Tang Monk, just to eat his flesh and drink his blood. But for various gods, there are several other ways to extend their lifespan or achieve immortality.

The first is ginseng fruit, the second is Laojun’s elixir, and the third is flat peach. Compared to flat peaches, one or two are too troublesome. According to the original description, ginseng fruit production is very small and takes a long time to mature. Only thirty ginseng fruits can be produced in ten thousand years, and they are still firmly occupied by earth immortals. Although Laojun's elixir can also prolong life, its yield is low, and it cannot be practiced all the time.

Eating flat peaches is a shortcut to immortality, and whether the effect of flat peaches is immortality or increasing one’s lifespan depends on the quality of the peaches. The number of flat peach trees is limited, and there are only 3,600 of them. Each of the 1,200 trees is divided into a grade, and the maturity years of each grade are three thousand, six thousand and nine thousand years.

The flat peach that has been cooked for nine thousand years is the most powerful. Ordinary people can live as long as the sun and the moon after eating it, which is true immortality. As for flat peaches that have been matured for three thousand years and those that have been matured for six thousand years, although ordinary people can become immortals and greatly extend their lifespan after eating them, they cannot truly achieve immortality. Otherwise, why are there old and young gods in heaven?

Although "Journey to the West" can be regarded as one of the four great masterpieces, there are still many loopholes in many settings, one of which It’s a question of ripening of flat peaches. According to the speed of time passing by one day in the sky and one year underground, 3,600 flat peach trees are not enough for the gods to eat, let alone hold a flat peach party.