Hi LongChen,
The blankness is a form of absorption where the knowing faculty of consciousness is temporarily suspended. Complete clarity and Presence without a 'Self' is more crucial.

The 'Self' that is created over countless lives of attachment cannot be underestimated.
We are in almost helpless bondage that our perceptions are shaped and held in a sort
of hypnosis that we feel, think, experience and deduced our understandings from the
perspective of an 'I'. Thus analytical understanding derived from the glimpse of
the Pure Presence Reality will very quickly get distorted.
When Presence is experienced with the six sense doors shut,
Presence is experienced as a form of "I AMness".
When Presence is experience with six sense doors widely open,
Presence is experienced as a form of "I AM All".
However neither experience tells us the TRUE NATURE of Pure Presence.
Even the very sense of Realness, of Existence, of Life and Vividness is so strong,
due to the sense of 'I' there will be a sense of location somewhere,
and the true face of Pure Presence remains hidden.
The mind is just not used to knowing the absolutely nothing, non-local,
nowhere to be found yet pure, brillance bright and ever luminious.
It will locate, it will find, it will grasp.
There must come a time for the mind to let go of itself completely.
If we are bold enough to let go and enter into the world that is wordless,
labelless and thoughtless, and if this is substained, wisdom and insight will arise.
This wisdom is the extraordinary Clarity, Vividness and Realness, wholeness whole.
It is crystal clear filling all spaces and places.
Both in silence and in noise, in blankness and somethingness.
Those that experience the Pure Presence will appreciate this crystal clear reality.
This re-visting of Pure Presence will be thorough and entire.
There will be no doubt.
Buddhism Emptiness is deep and profound. Do go into it.

Happy Journey