Despite the recurrent ravages of fire and earthquake and the devastation of the Pacific War, a sizeable volume of documentary material survives from Japan's Tokugawa period (1603–1868). Although its government archives may not be as large as those of the older centralized states of western Europe, the written record of the daily life of the Japanese people compares favourably with that of any other people over the same period. Several factors have counterbalanced Japan's unusually high incidence of natural calamities. At the time, literacy was more widespread than in most other countries and paper was plentiful and reasonably cheap. The “Tokugawa system” was effectively designed to reduce social, occupational, and geographic mobility to a minimum, so that, particularly in rural areas, a given family occupied the same station and fulfilled the same role for a long period. To a lesser extent, this was true even of commercial families. The popular idea of the impermanence of trade as a vocation was true only relative to the ideally almost immutable situation in agriculture. Strangely enough, it was the daimyo, members of the highest class, who, at least in the earlier period, were most mobile. Because of the continuity of family roles over long periods, records of, say, the late seventeenth century still had some relevance for descendants in the mid-nineteenth century, and so they tended to be preserved. Particularly in cities and towns, the rapid changes associated with the breakup of the Tokugawa system were undoubtedly accompanied by the loss of many records.