Concentration's Meaning

Is such an experience very advanced?

The goal of Concentration meditation is to lengthen the amount of time you can give unbroken attention to your meditation object. A secondary goal could also be given to move through the Jhanas as your practice gets stronger. The attainment of the Jhanas can be seen as more "advanced" practice, although they tend to arise naturally as you progress.

More so, does unawareness imply literally not seeing/hearing/etc. or merely not being solicited by such distractions?

In higher Jhanas, yes it is the case that some sensations will seemingly "drop away" as your focus heightens on your meditation object, although reaching these higher Jhanas are not required for gaining insight or becoming enlightened. This is what is meant by unawareness in a Jhanic state.

When you are not in a Jhana though, you will find there is still the jumping of awareness to different sense doors. This may happen very quickly and without being noticed which gives the illusion of you observing other senses while you are focusing on your meditation object. It is important to remember that this is an illusion, and it is impossible for the attention to be directed to two things at the same time. Awareness must jump from one thing to another in order for both to be perceived.

If you catch yourself observing a thought, as long as you bring your attention back to your meditation object, you are doing concentration meditation correctly. If you keep practicing in this way, you will lessen the thought stream as well as increase the length of time you are able to hold your attention.

Is attention placed upon the object consistently more important than thought reduction?

Attention placed on the object is important for doing insight meditation. The longer you can hold your attention, the greater the chance you will be able to observe insights that will profoundly change your understandings.

Thought reduction is also important. It is very easy to get wrapped up in the content of what is appearing. This is the same reason why we suggest closing our eyes while meditating. The content of what we observe can be very distracting. Thoughts in particular are more often than not misleading, and reinforce the beliefs that hold you in Samsara. The less distractions we can have while focusing, the easier it will be to observe the processes that are occurring.

Is any of these more important?

I think the two honestly go hand in hand. With only one and not the other, you are at a major disadvantage compared to if you had both. You are correct in your descriptions that they are both very useful tools that help us discover the truth about reality. I would suggest continuing your concentration practice with the intention of cultivating both.

I hope your meditations are fruitful and wish you nothing but love.

1. The practitioner can't remember any object of unawareness mind, sleeping, but he can clearly remember every object, mind, and mind factors of concentration meditation.
2. Unawareness mind, sleeping, is a resultant (Vipaka), but concentration meditation is karma (Karma).
3. Unawareness mind, sleeping, doesn't give any resultant, but concentration meditation gives resultants.
4. Unawareness mind is sleeping, ignoring the object, but concentration meditation is doing 30-36 jobs to the object.

Concentration meditation is strongly thinking of the only one object. It doesn't stop to think. Only unconsciousness mind, sleeping, is not thinking and the concentration meditation is not unconsciousness mind.

Concentration is a poor translation of samadhi. Samadhi means meditative state. And right samadhi is one with strong mindful awareness. Deep samadhi is a state of absorption into the meditation object.

There are also characteristic states of samadhi called jhanas which generally implies prominence of a particular mental quality (physical pleasure, mental joy, contentment and equanimity). However, the depth of each of these varies and are often debated between schools. This brings in the classification between commentarial jhanas (very deep states) vs sutta jhanas (just enough absorption to investigate phenomena).

Some schools prefer complete absorption as you imply in your question. Others, just enough absorption to have stable attention and plenty of awareness for insight practices. Certain suttas imply this sort of samadhi:

Monks, secluded from sense pleasure... a monk enters and dwells in the first jhana. He steeps, drenches, fills and suffuses his body with the rapture and happiness born of seclusion, so that there is no part of his entire body that is not suffused with this rapture and happiness. Just as a skilled bath-attendant or his apprentice might strew bathing powder in a copper basin, sprinkle it again and again with water, and knead it together so that the mass of bathing soap would be pervaded, suffused, and saturated with moisture inside and out yet would not ooze moisture, so a monk steeps, drenches, fills and suffuses his body with the rapture and happiness born of seclusion, so that, there is no part of his entire body that is not suffused with this rapture and happiness born of seclusion. (D.i,74)

There are two ways we typically know the presence of thoughts (The Mind Illuminated by John Yates PhD et. al). Attention and awareness. You attention can be stably on the breath and you mindful awareness can see thoughts and distraction come and go. This shows maturity of practice and there is a sense of standing aback and watching the breath. Thoughts stop arising as you consistently ignore them. It's a learned behaivour (unification of the mind aka citta-ekagatta) where the mind system is together working on stabilizing attention and observing the meditation object. This is the required amount of samadhi per a lot of teachers to begin insight training as your mind is now a sharp sword that can cut through anything without getting caught up.

Further and more in depth discussion on this topic can be found here:

1. https://www.accesstoinsight.org/lib/authors/gunaratana/wheel351.html

2. http://www.leighb.com/jhanas.htm

The bottom line though is that samadhi is a joyful, restful, alert and mindful state. It should ideally be nourishing and nurturing.