This essay develops a temporal and conceptual framework for analyzing some core processes in the political economy of Japan and in the political economy of two-party systems in general. It takes as a case study the era of “Taishō democracy”. The two-party politics of the era, originating out of the Taishō political crisis of 1912–13, were shaped by an opposition between the so-called of fiscal-monetary expansion and the so-called of retrenchment. The “positive-negative” divide structured a wide range of policy domains, including fiscal policy, monetary and foreign-exchange policy, diplomatic policy, military policy, social policy, and industrial policy. This essay constructs a chronology of this policy dialectic across multiple policy domains and contributes to theoretical discussion of policy fields, polarities, and regimes. It concludes by making a cross-temporal comparison to policy swings in the 1990s.