Sino-Japanese controversy over the Senkaku/Diaoyu/Diaoyutai Islands: An imminent flashpoint in the Indo-Pacific?

The 50-year-old controversy between Japan, the People's Republic of China (PRC) and Taiwan over the sovereignty of a group of tiny, uninhabited islets and rocks in the East China Sea, administered by Japan and referred to as the Senkaku Islands in Japan, as the Diaoyu Islands in the PRC and as the Diaoyutai Islands in Taiwan has become a proxy battlefield in the growing Sino-US great power competition in the Indo-Pacific, against the backdrop of a widening Sino-Japanese power gap. Since 1971, when the PRC and Taiwan laid claim to the contested islets and rocks for the first time, challenging Japan's position of having incorporated them into Japanese territory as terra nullius in 1895, possible avenues for settling the controversy have either been unsuccessful or remained unexplored. The PRC's meteoric economic rise and rapid military modernisation has gradually shifted the Sino-Japanese power balance, nourishing the PRC leadership's more assertive, albeit failed, push for Japan to recognise the existence of a dispute. Two incidents in the 2010s, perceived by the PRC as consolidating Japan's administrative control, led to the PRC starting to conduct grey-zone operations in the waters surrounding the islets and rocks with increasing frequency and duration, to reassert its claims and change the status quo in its favour without prompting a war. The EU has held a position of principled neutrality as regards the legal title to the disputed islands. However, the risk of unintended incidents, miscalculation and military conflict arising from the unresolved dispute poses a challenge to regional peace and stability and to the EU's economic and security interests. The EU's 2021 Indo-Pacific strategy takes a cooperative and inclusive approach, to promote a rules-based international order and respect for international law. This may include a greater Indo-Pacific naval presence under the strategy's maritime security dimension.