Published online by Cambridge University Press: 08 November 2022
The effects of the 1990s reforms to the electoral system of Japan's House of Representatives have been among the most frequently discussed topics in political science research on the country. These reforms saw the replacement of a hitherto single nontransferable vote (SNTV) system by a mixed-member majoritarian (MMM) system with a strong Single Member District (SMD) and a weaker Proportional Representation (PR) component. Many studies have suggested that the reforms may have had significant impact on the strategies of political parties. Generally, SMD systems have been widely thought to favor larger parties, while PR systems are more beneficial to small and medium-sized parties. On the content side, larger parties seeking control of the government would try to win the support of large numbers of floating voters by campaigning on universal/programmatic policy appeals, as opposed to particularistic interests. In contrast, smaller parties would cater towards their core supporters’ preferences. Previous studies have noted that the old SNTV system in Japan had produced results similar to PR systems (Reed 2003). Japan's electoral reform may have thus changed the strategy of large parties, which would need to win more seats in the SMDs to gain (or hold onto) power, while smaller parties have continued to try and win seats via the PR tier. Therefore, the reform provides valuable research material in so far as we can simultaneously observe different effects by the SMD and the PR systems on parties of different sizes.