Japan’s debate over the constitutionality of potentially offensive military strikes dates back to a 1956 statement made on behalf of then prime minister Hatoyama Ichirō. It said that striking enemy missile bases should be permissible within certain limits: Japan can take only the “minimum measures unavoidably necessary” when “no other measures” of self-defense are available in the face of an “imminent illegal invasion.” This statement became the bedrock of all future deliberations that sought to clarify Hatoyama’s interpretation, as part of a broader process to reconcile Japan’s exclusively defense-oriented security policy (senshū bōei)—which prohibits the procurement of certain offensive weapon systems—with pressures caused by the continuing evolution of modern warfare.
The strike debate began as a hypothetical exercise but became increasingly concrete from the late 1990s with a growing North Korea threat. China’s recent military rise and North Korea’s continued missile and nuclear development have put renewed focus on this issue, and it will feature prominently in the U.S.-Japan Roles, Missions, and Capabilities (RMC) dialogue that is taking place now through 2022.
Three main components make up the strike debate: When exactly can Japan use force overseas for self-defense? How should “no other measures” be defined? How are strike capabilities for self-defense reconcilable with the general belief that Japan’s constitution prohibits offensive war-waging weapons? More recently, specific terminology has been used to help differentiate between the subtle nuances of what should (and should not) be allowed, such as how a “preemptive strike” might differ from a “first strike,” or a “standoff weapon” might differ from one meant to strike an enemy base.
The following historical timeline of statements by senior Japanese officials helps answer these questions by highlighting relevant quotes from politicians (with original Japanese and our English translations) and providing necessary background on the context behind their statements. A glossary is included at the end, providing our assessment of what certain Japanese terms mean with regard to the government’s evolving defense policy and military procurement plans.
1 This digital feature builds on earlier work in James L. Schoff and David Song, “Five Things to Know About Japan’s Possible Acquisition of Strike Capability,” Carnegie Endowment for International Peace, August 14, 2017, https://carnegieendowment.org/2017/08/10/five-things-to-know-about-japan-s-possible-acquisition-of-strike-capability-pub-72710.