2026 KGRI Working Papers
The Reality of Japan's Active Cyber Defense: Lessons Learned from the Evolution of Cyber Deterrence through U.S. and U.K. Cyber Operations Since the Late 2010s
Cyberspace is referred to as the fifth operational domain, following land, sea, air, and space. With the rapid increase in the importance of cyberspace in modern society, it has become essential to deter cyberattacks and prevent further attacks.
Under these circumstances, Japan finally enacted the “Cyber Response Capability Enhancement Acts” in May 2025, initiating active cyber defense. Meanwhile, cyber-advanced nations like the United States and the United Kingdom have already been conducting offensive cyber operations in the “the gray zone,” i.e., the area between armed conflict and peacetime, since the late 2010s.
These operations are carried out not only against non-state actors, including hacker groups, but also against state actors, and information on counterattacks is disclosed through public attribution. The synergistic effects of these efforts have strengthened the cyber deterrence by punishment, which had previously been considered complementary.
This study analyzed the results of cyber operations conducted by the U.S. and U.K. since the late 2010s to examine the effects and limitations of these cyber proactive operations on cyber deterrence by punishment and by denial thereby proposing reality and challenges for Japan.
Germany’s Transatlantic Relations after the Zeitenwende: Continuity and Change under the Scholz and Merz Administrations
This paper examines the evolution of Germany’s transatlantic policy in the aftermath of the Zeitenwende (turning point), widely regarded as a truly historic turning point, focusing on developments under the Scholz and Merz administrations. It argues that while the Russian invasion of Ukraine marked a major shift in German security policy, subsequent changes in the transatlantic environment—particularly renewed U.S. pressure for greater European burden-sharing—have further accelerated structural adjustments in Germany’s defense posture.
The analysis traces how shifts in the transatlantic environment have interacted with domestic institutional and fiscal changes in Germany, developments in NATO and EU defence cooperation, and evolving public perceptions of the United States. It demonstrates that rising defence expenditures and Europe’s expanding role in supporting Ukraine reflect a broader structural shift in the distribution of responsibilities within the transatlantic alliance. At the same time, survey data show that while many Germans remain cautious about openly assuming a leading role in European military affairs, perceptions of the United States have deteriorated and support for increased defence spending has grown. This points to a broader societal reassessment of the transatlantic relationship.
The paper concludes that recent developments should not be interpreted as a weakening of the alliance but as part of a longer historical pattern of recalibration. A more capable and strategically autonomous Europe may ultimately contribute to a more balanced and sustainable transatlantic partnership.