The chapter attempts a description of the way itself, and the method is stranger than the content. Four times it says the way is elusive and vague, dim and dark, and four times it says that something is nonetheless in there: an image, a thing, an essence, something that can be relied on. Denial, then assertion, repeated until the reader stops expecting the denial to be the last word.
That structure carries the argument. A flat claim that the way contains an essence would invite the question of how anybody knows. A flat refusal to say anything would end the book at chapter one. What the chapter does instead is decline to resolve, and the refusal is the point: whatever is there is available to be relied on and not available to be inspected.
The vocabulary is worth watching, because it later acquires weight it does not carry here. The word rendered essence is jing, which in Chinese medicine and in later self-cultivation becomes a technical term for a vital substance. The word rendered genuine is zhen, which becomes the standard term for a realised person in the Daoist religion. Reading those later senses back into this chapter is the commonest way of making the passage say considerably more than it does.
The closing sentence changes the subject from description to access. The name has not gone away from antiquity to the present, and by it the beginning of all things is surveyed. Whatever is being described is not a distant object that has been glimpsed; it is what makes the looking possible.