Extending Duverger's Law to electoral districts of arbitrary district magnitude would imply just one "extra" candidate running in each race. In this paper we analyze equilibrium properties (possible equilibrium configuration and then existence) of a plurality electoral system returning more than one legislator per district. We look at sincere Downsian voters and strategically behaving candidates (who can change their policy platforms at no cost, while new candidates can enter the race). In Part II we find empirical evidence in favor of the implications of this analysis in the performance of actual SNTV electoral systems, such as the one in Japan and Taiwan