In the 21st century, Europe has continuously experienced serious crises-the European economic crisis after the bankruptcy of Lehman Brothers in 2008, the annexation of Crimea by Russia in 2014, a spate of terrorist attacks by extremists, a massive influx of refugees and the rise of far-right populist forces, and Brexit - and these problems are interrelated and complex. Meanwhile, the liberal international order has been threatened by the inclination of the United States toward a unilateralist foreign policy, the new rise of a dictatorial China, and the ambition of authoritarian Russia to regain power. It is of vital importance to understand the problems of Europe, which has maintained the liberal international order together with Japan, in considering how both can cooperate to uphold it.