The term "four portals" (yottsu no kuchi) is now virtually standard terminology in Japanese history textbooks, but it was a foreign concept when I introduced it some 30 years ago in an effort to overturn the prevailing image of early modern Japan as a country shut off from the rest of the world. Such a basic change in premise necessitated a complete reexamination of foreign relations in early modern Japan, including the role played by Nagasaki. In 1983, I proposed that the concept of sakoku be replaced with the concepts of kaikin (maritime restrictions) and a Japanese version of ka-i chitsujo (Sinocentric world order). More recently I have analyzed how the notion of closed and open countries took hold and helped shape the identity of the Japanese in the modern era.