The paper examines the relations between international aluminium cartels and the Japanese market. International cartelization had two main phases: the first one from 1926 to 1930, in which the European Cartel competed against the sole American producer to acquire additional quotas of international trade, and the second one from 1931 to 1939 in which the two groups reached peace by the settlement of a "world" cartel. Japan was the main competitive market for occidental firms during international competition and it was the first market in which Americans and Europeans were able to reach a compromise that pushed toward the world cartel of 1931. This cartel controlled formally 97 percent of world production, and it is often considered one of the most effective cartels of the 1930s. The success of the cartel was at the same time the first step toward an independent production in Japan, which became a producer in 1934, after some attempts during 1931-1933. The Japanese "aluminium rush," however, was not the sole result of an excessive capacity of control accomplished by the cartel: financial and monetary crisis, autarkic policy, military programs, strategic issues, and a general trend toward warfare pushed the Japanese government and the main zaibatsus into the aluminium affair, substituting progressively for imports. This paper wants to explore relations between international cartels, international trade, government policy, and the general economics of the 1930s, trying to contribute to the general debate on cartels about their effectiveness, their causes, and consequences.