In the received arrangement of the text, chapter thirty-seven is the last chapter of the Dao section, and chapter thirty-eight opens the De section. That two-part division gives the book the title by which it is best known, and it is the division this atlas records as the two portions Dao Jing and De Jing.
The silk manuscripts recovered from a Han tomb at Mawangdui in 1973 carry the two halves in the opposite order. The material corresponding to chapters thirty-eight to eighty-one comes first, and the material corresponding to chapters one to thirty-seven follows it. In those manuscripts this chapter is therefore not the hinge in the middle of the book but its final chapter, and the book ends on the world settling of itself rather than on the sage who acts and does not contend.
Two things follow from that. The first is that the familiar name of the book, which puts the way before power, records one arrangement out of at least two that circulated, and some modern editions accordingly reverse the order and use the alternative title. The second is that the position of a chapter is a fact about a particular edition rather than about the text, and arguments that depend on a chapter opening or closing a section have to say which edition they mean.
The chapter divisions themselves are an editorial layer, added in the course of transmission, and the eighty-one chapters became standard because the received recensions used them. They are a genuinely useful apparatus for reference, which is why this atlas records them, and they are not a feature of the earliest material.