Concentration Vs Meditation

[LSD-Rumi]

"The practice of concentration is almost identical to the practice of
concentrative meditation with only one fundamental difference. When you
practice concentrative meditation, you allow yourself to slip into a state of
ascending consciousness. While doing the yogic practice of concentration,
however, the sole focus is to improve the duration and quality of your
concentration (which you can then use to enjoy better meditation)." 

"For example, let’s say you hold a session of concentration for ten minutes.
During those ten minutes, you should be alert, in one posture – still like a
rock or tree, focusing keenly on the object of concentration and trying your
utmost to maintain lucidity. Maintaining lucidity means that your mind may
become dizzy, or the image of visualization has disappeared, or the sound
of the mantra just got lost in distractions and deviations. At that time you
remind yourself of your resolve to concentrate and bring back your mind to
the object of concentration; this is lucidity."

Om Swami

Watch this video if you want to more depth.

 

Edited January 7 by LSD-Rumi

[Ishanga]

He's basically talking about  Dharana the sixth limb of yoga. This is one pointed focus, first on a object of choice, you practice this (after completing/mastering the first 5 before the 6th step), then afterwards  your focus is just there, and can be maintained at will, when this happens then comes contemplation with no judgements, after this comes Samahdi where You experience oneness for periods of time, there are like 7 different kinds of Samahdi, nothing new in what he is saying...