일본국제법학계의 ‘대체적 권원론’상 ‘재확인’ 법리의 국제법적 문제점 검토

Since its defeat in World War II, Japan has sought to legitimize its claims to formerly occupied territories by distorting the interpretation of international law under the pretext of “restoring lost territories.” These efforts have produced a series of theoretical frameworks aimed at justifying Japan’s territorial assertions. In the context of Korea, such discourse may be broadly characterized as “Japanese studies on territorial title under international law concerning Dokdo.” Among the various works reflecting this line of argument, a notable Englishlanguage publication articulating the official Japanese government position is Japan’s Territory under International Law, published in 2024 by the Japan Institute of International Affairs (JIIA). Consistent with prior approaches, this book attempts to rationalize Japan’s territorial claims through a selective and distorted application of international legal principles. This paper critically examines the “reaffirmation” doctrine proposed by Masaharu Yanagihara in the aforementioned volume as a modern alternative to conventional notions of territorial acquisition over remote islands. Although Japan has previously invoked this “reaffirmation” theory, it has been applied almost exclusively to the case of Dokdo, with no other precedent identified. Building upon this foundation, Yanagihara introduces a new example- the case of Iō-tō (硫黄島, formerly called ‘Iwo Jima’)-which warrants further scrutiny. Accordingly, this paper reevaluates the legal and theoretical validity of the “reaffirmation” doctrine, focusing on its application to the Iō-tō case.