Low City versus High City divide
Edo was physically and socially split into the Shitamachi, the flat eastern lowlands along the Sumida where merchants and artisans lived packed together, and the Yamanote, the western hills of samurai estates. Seidensticker uses this split to explain how modernization played out: the High City took up Western institutions, universities and bureaucracy, while the Low City held the city's plebeian arts, festivals and pleasure quarters. Tokyo's cultural center of gravity moved steadily west and uphill as a result.