Exactly how much concentration is needed to attain Awakening?

Stable one-pointedness in the degree corresponding to what is known as ‘Access Samādhi’ to some and ‘Jhāna Light’ to others. Other aliases this samādhi is known by include ‘samatha’, ‘the first proximate stabilization of calm abiding’ and ‘shi-neh’.

Is jhāna heavy absolutely necessary?

Cultivation of ‘jhāna heavy’ is totally unnecessary for achieving the first stage of Awakening, sotāpanna, although it will spontaneously occur at the time of attainment. It becomes prevalent in the stage of sakadāgāmī and onward, developing naturally and easily.

Is dry insight sufficient?

Trick question. If you examine so-called ‘dry insight’, it is a method that involves achieving the level of samādhi identified as ‘access’ or ‘jhāna light’ above, but without strictly limiting oneself to using a fixed object during the process. It has the advantage of developing a high level of sati, while pure samatha practice can result in access samādhi or jhāna with significant dullness and relatively little sati.

Mahasi Sayadaw provides a precise description of access samādhi in the Progress of Insight but he calls it “Knowedge of Arising and Passing Away”. U Pandita in In This Very Life and On The Path To Freedom describes exactly the same thing in very similar words, and even explicitly labels it as “Vipassanā Jhāna”, in which the first three vipassanā jhānas are unmistakably what is otherwise known as “access samādhi”, or in our little circle, “jhāna light”.

As so many great masters of centuries past have repeated over and again, there is no Insight without samādhi, and samādhi without Insight cannot bring Awakening.A better question would be: “Is dry insight practice as effective at developing the necessary concentration as samatha followed by insight?”My answer: Perhaps for some, but probably not for most people.

And the distinction between access samādhi and khanika samadhi is more apparent than real when one has done this practice for a while. What is the difference between stable one-pointedness that lasts one hour and stable one-pointedness that lasts for 30 minutes? Duration, nothing more. What is the difference between access samādhi sustained for five minutes and access samādhi sustained for five seconds? Only 295 seconds, nothing else. I am sure that those of you who have become skilled at access, aka jhāna light, have noticed that after you have been doing this for a while you can shift the attention from the meditation object to the light, or the experience of pīti-sukha, or the clarity of the mind, and so on without losing focus. Some of you have probably noticed that the mind can even dabble in some discursive thought along the way at the access/jhāna light level without losing its stability. It is only in the early stages of achieving this samādhi that such transitions of object cause loss of stability.

What makes Mahasi style Vipassanā practice special is that by making the arising and passing away of momentary experience its primary focus, it allows us to know what is going on behind the seemingly continuous and stable perceptual continuum we usually dwell in.

For those of you who are familiar with the physics of light, it has the characteristics of both a wave and a particle simultaneously. If you design an experiement to reveal its wave-like properties, that is what you find. If you look instead for its particle-like behaviour, that is what you see. Does this remind anyone else but me of jhāna (heavy type) and bhanga-ñāṇa?

Once there is access samādhi, you can go either of two ways with it, just like the physicist can with light. Take the khanika path and it is Access to Insight (Mahasi style). Take the apana path and it is Access to Jhāna.