This is a lot of rubbish
Much of the Zen found in the West is Soto Zen. More specifically it is Dogens Soto Zen. It is important for beginners to know that Dogens Zen is not the Zen of China or Korea which are more congruent with Mahayana Buddhism and certainly not far away from the Pali canon (Nikayas/Agamas).
In a nutshell, the Soto teachings of Dogen believes that the ultimate meaning of Buddhism lies in the practice of zazen (lit. seated meditation), that is, just sitting. On this same track, this means that for Dogen, Buddhism and zazen are fundamentally the same thing. Zazen is Buddhism. Buddhism is zazen.
For anyone who has studied the Buddhist canon, Dogens Zen is quite a radical and unsupported. Neither the Mahayana canon nor the Pali canon provide any good evidence for his view when, for example, he claims that birth and death is nirvana. Both canons essentially teach the realization of nirvana which is transcendent; which is beyond the pale of samsara in which the cycle of birth and death take place. A passage from the Mahprajpramitashstra describes nirvana in more concise terms: Nirvana is the unborn, unextinct dharma; it is the ultimate reality, the supreme end. Such a realization requires more than sitting in a full or half lotus posture.
Dogens own enlightenment in China, which he believed to be quite profound, helped him to realize that we need not search for anything, especially enlightenment or Buddhahood, since we are already Buddhasin fact, everything is the nature of Buddha. Dogen imagined by just sitting, like the Buddha did supposedly after he left the five ascetics, we too can realize that everything, just as it is, is perfect. This means that zazen is, itself, the practice of perfectly realized truth. It is the gate to the real world.
Dogen basically wants us to understand that when we just sit, or the same, practice zazen we are abiding in Buddha reality itself. In zazen we are as we are and the external world is as it is which means that both are onethe o! neness o f reality. But this is a lot of rubbish.
On a personal note, many years ago when I studied Soto Zen with my teacher, I remember how I enjoyed just the pure act of sitting in our small zendo. I was told sometime later that this was enlightenment/practice. But something deep down inside of me said this is not the Buddhas enlightenment. It was hard to believe that just sitting was the Buddhas enlightenment given the other material that I had read. At the time, I had read all the books in the temples small library which I was put in charge of. Apparently, what good karma I had smiled upon me and delivered me from this den of crazies! (During this same time I had discovered D.T. Suzukis translation of the Lankavatara Sutra which helped to make my departure from Soto easy. There was no comparison between the two, one wasnt Buddhism, the other was.)
