In the latter half of the Edo period, as the Japanese became aware of the trends affecting foreign countries, it became clear that the Shogun's samurai retainers would not be able to master the bewildering array of specialized fields by themselves.
江戸期後半になって諸外国の動向が伝わって来るにつけ、武士である幕臣だけではさまざまな専門分野に対応できなかった。