Following Prime Minister and Liberal Democratic Party President Yoshihide Suga’s surprise Sept. 3 announcement that he would not seek re-election as party leader, the ruling LDP was thrown into confusion as to who might stand in the Sept. 29 election. The campaign officially begins Friday, and whoever wins will need strong support from Diet members as well as LDP party members in order to become the next president and — because the LDP is the largest ruling party — prime minister.

What is the structure of this year’s election and how is it different from last year’s?

In the initial round of voting, a total of 383 Diet members will cast their ballots. Another 383 votes will be up for grabs across the nation's 47 prefectures, under an allocation system known as the D’Hondt method, for a total of 766 votes. This allocation method has been adopted by parliamentary systems in dozens of countries.