UK-Japan military exercises and mutual strategic reassurance.

The United Kingdom (UK) and Japan have conducted unprecedented military exercises as each other's closest security partners in Asia and Europe, respectively. Despite publicly avowed closeness, these military exercises were not predicated on formal alliance commitments or deterrence of common adversaries underpinned by shared threat perceptions. Addressing this puzzle, a hitherto-overlooked perspective of mutual strategic reassurance for trusted partners is proposed here. This paper derives hypotheses from existing – but relatively under-developed – literatures on military exercises and reassurances that locate the drivers of reassurance in the needs and weaknesses of the other. What stems from this starting premise is an importance placed on high-level diplomacy and adjusting military deployments to allay each other's strategic concerns. These hypotheses are tested by presenting original interview data supplemented with discourse analysis of both primary and secondary sources. The findings suggest that effusive diplomatic language vowing politico-strategic support for each other, reinforced by ground-breaking military exercises mutually reassured UK concerns about retaining post-Brexit global standing and Japan's apprehension over its dire geo-strategic context. While not quite deterrence or alliance, these military exercises enabled the UK and Japan to transform their predominantly trade-based relationship into a more defence-oriented one. [ABSTRACT FROM AUTHOR]