第一编介绍了元世祖忽必烈经营南海的整体情况，指明其对陈朝政策乃是以占城为据点支配南海整体大战略中的一环，进而阐明了元朝与陈朝的外交、以及1284-1285年及1287-1288年元朝出兵的详细经过。通过使用地图对战斗经过的研究，相对于“不知晓实地仅使用中国文献来研究”的中国史、元史研究者，山本达郎对陈朝方面动向的详细解明，并加以正确的地理考证，实现了前者无法达到的精度，使读者叹为观止。研究明朝永乐帝的对越政策、对越出兵，明朝统治越南的实际情况及黎利等人反抗而致使统治崩溃的第二编，也同样细致且高瞻远瞩。即便在当时引领越南史研究的法国学界，也尚未存在如此研究。其对明朝设置府州县的位置的考证，直到现在也仍然是各种研究的基础。

In this revisionist history of the eighteenth-century Qing Empire from a maritime perspective, Ronald C. Po argues that it is reductive to view China over this period exclusively as a continental power with little interest in the sea. With a coastline of almost 14,500 kilometers, the Qing was not a landlocked state. Although it came to be known as an inward-looking empire, Po suggests that the Qing was integrated into the maritime world through its naval development and customs institutionalization. In contrast to our orthodox perception, the Manchu court, in fact, deliberately engaged with the ocean politically, militarily, and even conceptually. The Blue Frontier offers a much broader picture of the Qing as an Asian giant responding flexibly to challenges and extensive interaction on all frontiers - both land and sea - in the long eighteenth century.