Factbox: Potential candidates to become Japan's next prime minister

Here are details about the people who might become Japan's next prime minister.

A former foreign minister, Kishida had been considered the likely heir of Shinzo Abe, who resigned last September, but the low-key lawmaker from Hiroshima typically ranks low in voter surveys. He came in second in last year's party leadership poll.

Kishida hails from one of the LDP's more dovish factions and is seen as lukewarm about revising the pacifist constitution.

Announcing his candidacy, Kishida called for reducing income disparities and pledged support to the economically vulnerable, such as workers in non-regular employment and women, in contrast with Suga, who has stressed self-reliance.

This week, Kishida said an economic stimulus package worth "tens of trillions of yen" was needed to combat the coronavirus pandemic. He also said Japan must maintain ultra-low interest rates to support the pandemic-hit economy.

He has said he was running to show the LDP "listens to the people and offers broad choices, and to protect our nation's democracy," a comment seen as a criticism of Suga's governing style.

An Abe disciple and former internal affairs minister, Takaichi has made clear her desire to become Japan's first female premier, and said she would introduce policies to fend off China's technology threat and help strengthen the economy.

Takaichi said she wanted to work on issues left unfinished by previous administrations, such as achieving 2% inflation, and to introduce legislation "that prevents the leakage of sensitive information to China".

She said an extra budget needs to be compiled as soon as possible to bolster Japan's medical system, which is under strain because of the pandemic.

A member of the party's most conservative wing, she often visits Yasukuni Shrine, a controversial memorial to Japan's war dead, and has opposed allowing married couples to keep separate surnames.

However, it is not clear whether she will obtain the 20 lawmaker backers needed to run in the leadership election.

In charge of Japan's rocky vaccination rollout, Kono ranks high on the list of lawmakers voters want to see succeed Suga.

Educated at Georgetown University and a fluent English speaker, the social media-savvy Kono has served as foreign and defence minister and holds the portfolio for administrative reform.

Kono has a reputation as a maverick but toed the line on key Abe policies. He has differentiated his conservative stances from those of his father, former chief cabinet secretary Yohei Kono, who authored a landmark 1993 apology to "comfort women", a euphemism for women forced to work in Japan's wartime military brothels.

A member of powerful Finance Minister Taro Aso's faction, Kono has not indicated whether he intends to run in the leadership race.

A former defence minister, Ishiba regularly ranks high in voter surveys but is less popular with party MPs.

A soft-spoken security maven and rare LDP critic of Abe when the latter was in office, Ishiba has also held portfolios for agriculture and reviving local economies.

He defeated Abe in the first round of a party poll in 2012 thanks to strong grassroots support, but lost in the second round when only MPs could vote. He has since lost two more times.