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In page Japanese sword:

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The word katana was used in ancient Japan and is still used today, whereas the old usage of the word nihontō is found in the poem[1] the Song of Nihontō, by the Song dynasty poet Ouyang Xiu. The word nihontō became more common in Japan in the late Tokugawa shogunate. Due to importation of Western swords, the word nihontō was adopted to distinguish it from the Western sword (洋刀, yōtō).[citation needed]