Why Buddha taught Impermanence? (wu chang)
It's because it is to break our attachment to Permanence (you
chang). The fact is, there is not a moment of thingness, not a
moment of 'chang'. Empty. No two moments are the same, there is no
continuity of 'things', only Yuan Qi.
Why during zen sessions the zen master shouts KATZ?
Wake you up from your
process of thoughts. Just awareness. What is this very moment...
just awareness. In this moment, there is just awareness, no
'thingness'. In this very moment, we dont think in terms of time,
we dont even know what time is it. It is a timeless dimension,
beyond space. How can there be permanence of 'things' then?
Years ago, (when I was still new to Buddhism), after reading a line
from heart sutra, 'emptiness is form, form is emptiness', I have a
small realisation. Prior to that I do not understand heart sutra,
but after that, everything seems clear to me. Our minds have always
been attached to 'thingness', grasping on form, names, concepts of
'things'. Form is emptiness, emptiness is form. Form does not
reject emptiness, emptiness does not reject form, they are not two,
not opposites.