In her book A Translucent Mirror, Pamela Crossley wrote that “The Ming empire (1368–1644) was perpetually engaged in a struggle against various peoples along its northern borders.” This bald statement contradicts conventional wisdom that the Ming dynasty, having endured Mongol rule for about a century, attempted to limit relations with foreign lands and developed a policy of isolation. In fact, the Ming empire became embroiled in numerous conflicts along its frontiers. Some of these clashes were defensive, but others were attempts to annex additional territory. The court resolved a few of these conflicts through diplomacy or withdrawal from alien lands, yet others festered throughout the dynasty. It scarcely enjoyed clear-cut victories. Nonetheless, such repeated battles necessitated improvements in military strategy and technology, and it is no accident that a spate of texts on the military appeared during this time. The first Ming emperor himself had to master principles of land and naval warfare in the course of defeating other rebel groups and in seeking to gain the throne.