The present research discusses whether Japan is currently a sovereign state or not. It is plausible to commence by stating that Japan’s sovereignty has been a malleable and contested issue in the 21st century—which derives its roots from the history of the U.S.-Japan relations. The U.S.-Japan relations are of tremendous significance if one is to comprehend whether contemporary Japan is a sovereign polity. Japan—having become a de-militarized country through the pacifist Article 9 of the Japanese Constitution in the aftermath of World War II and the atomic bombings Hiroshima and Nagasaki—has lost its sovereignty.1 Such a thesis may sound contested, given that Japan has never been a colonized state. Historically speaking, Western powers have never formally colonized Japan, yet Japan was a colonizer itself.2 It has, however, experienced formal semi-colonial situations, and Western colonialism has profoundly influenced modern Japan in wide-ranging ways. It is, nevertheless, incontrovertible that Japan has never been a colonized state as it is the case, for instance, the British Raj. Despite having remained a non-colonized country throughout its history, nevertheless, Japan’s extreme dependence on the United States for its defensive security purports that it is not a sovereign nation (discussed in the following paragraphs). Furthermore, the question whether Japan is a sovereign state or not in the 21st century has its origins rooted in the very text of the Security Treaty between the United States and Japan—which is the most quintessential record regarding the Japanese security policies of the United States and the U.S.-Japan relations, given that it is a bilateral agreement. Therefore, Therefore, it is the Security Treaty between the United States and Japan, along with its 1951 and 1960 revisions that have been the most notable deciding factor in determining whether Japan is a sovereign state or not in the 21st century