Trying by the force of will to suppress our thoughts and concepts to reach enlightenment is somewhat analogous to trying to stop the ripples on a pond by patting them down with our hand. It might even be looked upon as an act of madness. Zen's idea of having us stop our thoughts, including our concepts really means to see their substance or tathatā. This happens instantaneously. It just takes one glimpse. After that we are positioned correctly: the unconditioned substance looking at its compositions all of which are dependent on the unconditioned. Before this event occurred, we used thoughts and concepts to look for that which was beyond thoughts and concepts. Not a very wise way of trying to see true reality.
The instantaneity of this extraordinary seeing can be illustrated in the example of looking for our car keys. Although we don't know a lot of details about these keys, for example, what they are made of, one glimpse of them next to a stack of books is all that it takes. We have found them! After instantaneously seeing this substance, we realize that it has no color or sound. It isn't big or small. It transcends space and time. It is not born nor can it perish and so on. If we try to explain it to others, they say it is nothing or emptiness. Nevertheless, everything the Buddha said about it came to be true. Looking back, we realize that we have always had this substance.
There is a huge difference between, continually, suppressing our thoughts and concepts and seeing, exactly, what transcends our thoughts and concepts. Even if we get lucky and see this luminous substance or pure Mind, which has never been defiled by thoughts and concepts, it takes time to see all the implications this jewel possesses. This is a gradual process. It takes time to overcome our habit-forces (vāsanā) which favor conditionality and not the unconditioned. Day in and day out we go to this most perfect substance. We samādhi with it, so to speak, again and again for many years. This acts against our old habit-forces so as to redeem our true self which has long been a slave to ignorance.
In my own example, this process eventually culminates in a most amazing encounter with what can only be described as a super-being. If the unconditioned animative side of us (tathatā) is fully developed, which supersedes the temporal man of flesh, one truly develops into a new kind of being. When I encountered this being it asks, at first only one thing, "Show me what you know." And if you have not awakened to the unconditioned substance or tathatā, the story ends here. But if you have, the story continues in a thoroughly mystical way. All of this becomes a secret but only for the reason that the an-aryans, those who live in darkness and teach the worship of ignorance, don't wish anyone to know of the unconditioned! Such people are profoundly evil.