From Edo Culture: Daily Life and Diversions in Urban Japan, 1600–1868, by Nishiyama Matsunosuke, trans. and ed. by Gerald Groemer (U. Hawai‘i Press, 1997), pp. 41-43:
The center of Edo was the shogun's castle. At least until the Genroku period (1688–1704) the city was primarily the capital of the warrior. It was a teeming metropolis, a million strong, with men outnumbering women by more than two to one. Edo bustled with warriors, craftsmen, merchants, and performers from throughout the land. The upper class amused itself at the kabuki or in the Yoshiwara pleasure quarters; the activities of the big spenders captured the public imagination.My first younger brother was born in Tokyo, and so claims to be an "Edokko." But my other two brothers born in Japan have never been labeled "Kokurakko" or "Kyotokko" after their birthplaces. Until I read the passage above, I had never thought to ask why not.
The shogun, daimyo, and their retainers spent almost all their money in the city; Edo was a center of consumption. Originally, very little was produced there, neither daily necessities nor high-grade cultural artifacts. Instead, articles were imported from Kamigata, that is, from the Kyoto and Osaka area. Such goods were called kudarimono—quality products that had "come down" from Kamigata. Wares that had not "come down" were considered inferior: thus the origin of the word kudaran ("not come down"), meaning uninteresting or worthless. The sale of imported goods netted great profits for Edo branches of stores headquartered in Ise, Ōmi, or other provinces. From around the Genroku period these businesses, known as Edo-dana and located at Nihonbashi, Denmacho, and elsewhere, expanded greatly. This expansion signaled the rise of the Edo chōnin's economic power.
As mentioned earlier, Edo-dana were staffed exclusively by men who had come to Edo only to work. These men even saw to their own cooking, cleaning, and laundry. Unable to sink their roots in the city, Edo-dana employees remained perennial outsiders. During the latter half of the eighteenth century, however, a new type of individual appeared: the Edokko, a pure Edo chōnin, who was rooted in the city itself. The first recorded usage of the term Edokko occurs in a senryū [satiric, witty verse identical in form to more serious haiku] of 1771, and thereafter was used by many authors....
One finds no label corresponding to the Edokko in Osaka and Kyoto. No concept of an "Osakakko" or a "Kyotokko" exists; nor is there any parallel in Nagoya, Kanazawa, or Hiroshima. Thus we must ask why the idea of such a native arose solely in Edo. The answer to this question is simple. In Osaka, Kyoto, and other cities, almost the entire chōnin population corresponded to what the Edokko was in Edo. In the capital, however, a huge number of unassimilated provincials remained "outsiders," providing a contrast to the distinctly native Edokko. During the city's early years, this heterogeneous population grew larger and developed evenly; but by the second half of the eighteenth century a marked contrast between natives and nonnatives begins to appear. This contrast was not entirely missing in other large cities such as Osaka or Kyoto, but in Edo a much larger part of the population remained nonnative.
Within Edo there existed yet another distinction: the sharp contrast between the uptown (yamanote) and the downtown (shitamachi) areas. These terms can already be found in the hanashibon (storybook) known as Eda sangoju (Beads of Coral) published in 1690. The yamanote area was a diluvial terrace packed with warrior residences; the shitamachi area was an alluvial area with a concentration of chōnin dwellings. Since the chōnin class was further split between Edokko and a large population of Edo-dana "outsiders," Edokko were constantly confronted with a large number of people unlike themselves. The unmistakable character of the Edokko developed within this social context.
The Edokko's sense of nativeness that emerged during the second half of the eighteenth century fostered the efflorescence of Edokko culture. This unique culture was, however, not created by Edokko alone. Instead, it resulted from the interaction of three groups, each of which complemented the others: the warriors, the provincial chōnin "outsiders," and the Edokko.