Dan74 wrote:Within these traditions there have certainly been teachers who have taught jhanas or have considered jhanas as stages along the path.
Yes. For example, Changlu Zongze's Zuochanyi
This one teaching of meditation is our most urgent business. If you do not practice meditation and enter dhyāna, then when it comes down to it, you will be completely at a loss. Therefore, to seek the pearl, we should still the waves; if we disturb the water, it will be hard to get. When the water of meditation is clear, the pearl of the mind will appear of itself. Therefore, the Perfect Enlightenment Sūtra says, ''Unimpeded, immaculate wisdom always arises dependent on meditation." The Lotus Blossom Sūtra says, "In a quiet place, he practices the control of the mind, abiding motionless like Mt. Sumeru." Thus, transcending the profane and surpassing the holy are always contingent on the condition of dhyāna; shedding [this body] while seated and fleeing [this life] while standing are necessarily dependent on the power of samādhi. Even if one devotes himself to the practice his entire life, he may still not be in time; how then could one who procrastinates possibly overcome karma? Therefore, an ancient has said, ''Without the power of samādhi, you will meekly cower at death's door." Shutting your eyes, you will end your life in vain; and just as you are, you will drift [in saṃsāra].
I remember many years ago Ven. Heng Sure commenting about one monk from the CTTB who would regularly sit in dhyāna for 5+ hours at a time. And there's the reports of Ven. Xuyun remaining in samādhi for extended periods, once for a period of 18 days, and twice for periods of 9 days each: An Inquiry Into Master Xuyun’s Experiences of Long-dwelling in Samādhi
. Granted, these are exceptional cases, but dhyāna requires a dedicated, refined level of practice.