Most think of Zazen as a means to reach and attain some sought after enlightenment, somewhere down the road.
... In other words, by experiencing Zazen as complete, by dropping all thought of any other place or action to be or do in that moment, by just sitting without judgment or feeling of lack ... the self both drops away and is affirmed and fulfilled in that moment. All is complete.
ALL BUDDHA-TATHAGATAS TOGETHER
have been simply transmitting wondrous dharma and actualizing anuttara samjak
sambodhi [supreme perfect enlightenment] for which there is an unsurpassable,
unfabricated, wondrous method. This wondrous dharma, which has been transmitted
only from buddha to buddha without deviation, has as its criterion jijuyu
zanmai. For disporting oneself freely in this samadhi, practicing zazen in an
upright posture is the true gate.
[Kosho Uchiyama comments, "...we can understand this (jijuyu zanmai) samadhi of self-fulfillment and enjoyment as the samadhi or concentration on the self when it simply receives and accepts its function, or its spiritual position in the world."]
From: Talk on the Wholehearted Practice of the Way -
Kosho Uchiyama (with Shohaku Okumura, Taigen Daniel Leighton)
When the buddha-tathagatas each having received the one-to-one transmission of the splendid Dharma, experience the supreme state of bodhi, they possess a subtle method that is supreme and without intention. The reason this [method] is transmitted only from buddha to buddha, without deviation, is that the samadhi of receiving and using the self is its standard. For enjoyment of this samadhi the practice of [Za]zen in the erect sitting posture, has been established as the authentic gate. From: Bendowa - A Talk about Pursuing the Truth - Nishijima-Cross