Mujo (absence of absolutes) (無常)

Mujo (anitya in Sanskrit) points out that all beings in the present world disintegrate and are in constant transition without being stationary.
Buddha explained it as "phenomena that exist or do not exist due to omens.'

Summary

When Buddha achieved nirvana, most of mankind saw the human world as constant despite being mujo, happiness despite being full of suffering, themselves as not selfish despite being selfish, and considered impure as pure. This is called as Shitendo (the four inversion or contrary view).

There are two explanations for this 'mujo,' 'momentary,' (moment-to-moment impermanence) and 'continuous impermanence.'
Momentary impermanence pointed out the form of one disappearing as setsuna (a moment or instant) and instance, and continuous impermanence indicated the life and death processes of humans dying, plants withering, and water evaporating.

This mujo is referred as "Shogyo Mujo" (All things must pass) in the head of three and four seals of the dharma and is considered to be the foundation ideology of Buddhism.

In addition, Mahayana Buddhism denied what mankind considered 'constant' and believe it to be 'mujo,' that only Buddha and nirvana are 'Joju' (actual existence) of truth. This is called the four virtues of nirvana (absolute happiness, true self, and purity), but the Nirvana Sutra of Mahayana Buddhism explains it more in detail.

Japanese and 'Mujo'

Medieval Japanese Classic Literature such as the 'Tale of Heike' that begins with "the voice of bells of Jetavana Vihara," "Tsurezure gusa" (Essays in Idleness) written by Kenko YOSHIDA, "Hojoki" (An Account of My Hut) of KAMO no Chomei that begins with 'no water is present when the flowing river stops running,' cannot be told without the Mujo view of Buddhism. To simply say 'flower' means cherry, and the Japanese love cherries because they are not permanent but give a feeling of mujo. While Westerners sought beauty in 'eternal beings,' many Japanese have a strong tendency to seek beauty in transforming things. The 'mujo' and 'mujo views' could be said to be unique characteristics of the Japanese concept of beauty that has grown over many years since the medieval era.