Samadhi aims to master one's mind by taking control of the mental processes.
The root cause of our suffering is desire - desire for something to happen (craving) or desire for something not to happen (aversion).
To eliminate this desire and gain freedom from suffering, Buddha recommended Bhavana or mental development.
Today, bhavana means feeling, any kind of feeling, but in Buddha's time, it referred to the two trainings of concentration (Samadhi) and wisdom (Pragya or Panna).
Samadhi comprises three parts of the Noble Eightfold Path.
Buddha prescribed various techniques for concentrating the mind, each suited to the particular person coming to him for training.
The most suitable one, however, one which Buddha himself practiced, was that of anapana-sati or awareness of respiration.
Respiration is a universally accessible and acceptable object of meditation. It is secular, non-religious and readily available to all.
The core idea is to become aware of ones breath, and not to control it in any way.
The first realization that hits you, as soon as you begin the exercise is that the mind is totally out of control - it keeps jumping from one thought to another, constantly running away from reality.
With patience and calmness, we keep bringing it back to the breath, to the present moment, away from the past and the future. This gentle training of the mind is called right effort.
We suffer due to our ignorance. Ignorance of reality.
Instead of witnessing the present, we continually relive the pleasant or unpleasant experiences of the past or fantasize about the future.
Dharma is the path of here-and-now.
Focusing on respiration develops awareness of oneself in the here and now.
Looking inward, we start to see the close interrelation between our emotions and breath.
When the mind is peaceful and calm, the breath is slow and regular.
But, as soon as negativity arises in the form of anger, hatred, jealousy, fear or passion, immediately breath changes too, and becomes shallow and heavy.
This allows us to witness the subtler reality (interconnectedness) of our mind and body.
Another reason why breath is preferred is because it is difficult to develop any craving or aversion for breath.
It happens of its own accord. We can't be greedy and want more of it. Neither can we develop aversion and ask less of it.
It is what it is.
Our moment-to-moment reality divorced of all illusion.
In the moment where the mind is fully focused on respiration, it is free from craving, free of aversion, and free of ignorance.
Even a brief moment of such purity is very powerful and challenges all our past conditioning.
In face of such moments of pure awareness, the past conditioning can't hold sway and releases its hold on us.
But, it doesn't give up without a fight.
As the accumulated sanskars or sankharas (conditioning) get stirred up, they start appearing as various difficulties, both physical and mental, which act as a hindrance to one's efforts to develop awareness.
The hindrance manifests in many forms, either as our impatience for progress (craving), or frustration and anger at slow progress (aversion), or lethargy putting us to sleep as soon as we sit for meditation, or skepticism about the teacher, or about the teaching or of our own ability to meditate.
At such a juncture, it is important to remember that the hindrance has arisen only in reaction to our success in practicing awareness of respiration.
If we persevere the hindrance gradually disappears.
The good part is that by the time it disappears, we are well on our way to cleansing our mind of all defilements and advancing toward liberation.
Fixing the attention on respiration develops awareness of the present moment.
Maintaining this awareness from moment to moment, for as long as possible, is right concentration.
Concentration is of many types - a hunter stalking his prey, a thief looking to break in, a person focused on satisfying his sensual desire, but none of these can lead to liberation.
For right concentration or samadhi, we must have as its focus an object that is free from all craving, all aversion and all illusion.
This is where breath serves a useful role in achieving samadhi.
Liberation requires still further work, beyond samadhi, where we go deeper into the sub-conscious mind and uproot the cause of suffering for good.
The second type of bhavana, or Pragya or Panna, takes us to the final destination.
Get my book, Meditation-Hacker: 7 Ancient Secrets to Crack the Inner-Bliss Code and receive valuable information on meditation that you can use to improve the quality of your health and life.