What is Shikantaza?

Wrote in Reddit: 

IMO Just Sitting (nothing but sitting) is like actualizing anatman. In seeing just the seen, in hearing just sound, in sitting just sit (shikantaza = just sitting).

"Shikantaza is to practice or actualize emptiness." - Shunryu Suzuki https://www.lionsroar.com/letters-from-emptiness/

"The zazen I speak of is not meditation practice. It is simply the dharma gate of joyful ease, the practice realization of totally culminated enlightenment." - Dogen

"SHIKANTAZA IS MEDITATION IN its simplest form. There are only three elements: body, mind, and breath. No gimmicks. Nothing to hold on to. Not even the breath. Breath is still present, of course, but we're not fixed on it. Earlier in this book I talked about tranquility (shamatha in Sanskrit) and awareness (vipashyana in Sanskrit). In shikantaza, these two are not separate. The mind settles, but not on a particular point. In shikantaza, Awareness is objectless and subjectless—there's no "you" who does shikantaza. It's as if concentration has been filed down to a single point—yet, at the same time, has expanded outward and is taking in everything: sights, sounds, feelings, sensations, thoughts, movements. And this Awareness is sizeless and timeless. In shikantaza we discover that there is no clear distinc-tion between self and other. Are you breathing? Or are you being breathed? You need not answer. There is no essential difference. Awareness is general and without location. It's been this way all along, but only now is it clear and obvious."

• Zen teacher Steve Hagen, "Meditation Now or Never"

"Buddha said in the Agama Sutras (Soh: Referring to Bahiya Sutta): "In the seen is just the seen, in the heard is just the heard." Our six senses are naturally free and unobstructed. So, in sitting meditation, just sit like that, letting the six senses function naturally and freely. Don't interfere with them, not even non-interfering interference. In essence, there isn’t an "I" watching or listening there. Thus, zazen is about allowing all phenomena to prove there's no you, not about you proving there's no you. The key is here; don't get it wrong. When you try to prove there's no you, an "I" is already there proving it. Is that forgetting the self? No!

So, how do all phenomena prove there's no you? What exactly are these phenomena?

The seen forms, heard sounds, smelled scents, tasted flavors, felt sensations of cold and heat, the arising and passing thoughts. All these phenomena are constantly telling you, there's no me! There's no me!"

"The six senses are truly just present, operating naturally within the true and unobstructed reality. This is the so-called natural, unobstructed functioning of the six senses. It's so natural, a matter of course. Only in the genuine practice of zazen, at that very moment, do you realize our mind is incredibly vast, its applications infinite. The six senses function naturally: eyes seeing forms, ears hearing sounds, nose smelling scents, tongue tasting flavors, body feeling touches, mind perceiving phenomena. All actions and movements are the Dharma Body. The six senses are unimpeded, free from attachment or aversion, equally interacting with arising and ceasing conditions, naturally liberated. Siddhartha Gautama Buddha himself said, if you can genuinely let all phenomena prove there's no you, sitting zazen honestly in this way, just the time it takes for an ant to crawl from your nose to your forehead is more beneficial than sitting for ten, a hundred years with an 'I'. If you seek the Dharma with yourself for a hundred billion years, it's impossible, forever impossible. Because there's an "I" wanting to become a Buddha!"Shikantaza," this method, is the authentic practice of zazen. Sitting in that moment is performing the Buddha's dignified conduct, Buddha's actions. The moment without delusion is Buddha's dignified conduct, hence this is called the method of great ease."

"I' is not right, 'no I' is not right, but meditation is happening! What thing is meditating? What is meditating? How do you resolve this? Some more enlightened Zen masters, like Zemu Xingdao, sometimes say 'meditation is meditating' for the sake of instruction, for convenience in teaching. Because he is experienced, whatever he says is right. Or in English, 'the universe is universing', the universe is sitting the universe, the universe is the universe. Some people, upon hearing this, might be even more baffled."

• Zen teacher Hong Wen Liang（Full article from my translation: https://www.awakeningtoreality.com/2023/12/shinkantaza-just-sitting-letting-all.html ）