FACTBOX: How Japan will pick its new leader

(Reuters) - The race to succeed Japanese Prime Minister Shinzo Abe is shaping up as a fight between 71-year-old lawmaker Yasuo Fukuda, an advocate of warm ties with Asian neighbors, and hawkish former foreign minister Taro Aso, 66.

The ruling Liberal Democratic Party (LDP) is expected to pick Abe's successor on Sept 23.

The new LDP chief is assured the Japanese premiership by virtue of the party's grip on parliament, which is expected to convene shortly after the LDP presidential race to formally elect a successor to Prime Minister Abe.

Below is a summary of key procedures for the ballot.

KEY DATES

1) Sept 15 - The LDP accepts candidates

2) Sept 23 - Voting to select new party president

THE 528 VOTERS 1) LDP members of parliament (3O4 from the parliament's lower house, 83 from parliament's upper house) 2) Three representatives each from the 47 LDP prefectural chapters (141 votes)

VOTING The winner must obtain a simple majority of the 528 votes. If no candidate wins that majority, there will be a second ballot between the top two candidates with most first-round votes.

PRIME MINISTERIAL ELECTION

Apart from the ruling LDP, some opposition parties are likely to nominate candidates for a vote in parliament's lower house to select a prime minister.

The LDP's candidate is certain to be named prime minister as the party holds a large majority.