Japan’s embattled centre-left Prime Minister Naoto Kan has pledged to step down once the March 11 quake and tsunami recovery is well underway, setting off speculation on who will replace him.

Here is a list of potential successors from the ruling Democratic Party of Japan (DPJ) who could replace Kan as early as this summer:

Seiji Maehara, 49:

Telegenic and relatively young, this conservative and hawkish former foreign minister was once dubbed “Japan's Tony Blair”, but has a funding scandal hanging over his head that led him to step down as minister in 2011.

Maehara gained prominence last year during a bitter spat with regional and historical rival China and neighbour Russia in separate island disputes.

Long seen as a politician of prime ministerial calibre, he is a self-made lawmaker in a political world long dominated by the offspring of former politicians. He led the party from 2005 to 2006.

A graduate of the elite Kyoto University, Maehara attended the private Matsushita Institute of Government and Management which uses tough workouts and meditation in its programme to forge modern political leaders.

Maehara quit the Kan Cabinet in March after admitting to receiving around $3,000 in donations from an ethnic Korean restaurant owner, a family friend since his childhood, in contravention of Japanese law.

Katsuya Okada, 57:

Okada is a former party chief with a “Mr Clean” image who served as a foreign minister after the DPJ came to power over two years ago.

Under the first DPJ premier Yukio Hatoyama, Okada handled a tricky row over the relocation of an unpopular US airbase on Okinawa island which badly strained US ties and ultimately led to Hatoyama’s downfall.

A law graduate from prestigious Tokyo University who also studied at Harvard, Okada is known for his deep policy knowledge.

Sometimes dubbed the “fundamentalist” or “RoboCop” for his strict adherence to principle and refusal of all gifts, even flowers and chocolate, he is also seen as inflexible and lacking a gift for negotiation.

A passionate supporter of denuclearisation, he had pushed China to reduce its nuclear arsenal, at times angering Beijing.

He is the second son of Takuya Okada, who turned his family business into one of Japan's two biggest supermarket operators, Aeon.

Yoshihiko Noda, 54:

The current finance minister is a fiscal hawk who has attempted to cut the industrialised world’s biggest public debt and fended off political pressure to stimulate the economy through greater public spending.

Also a graduate of the Matsushita Institute, Noda has supported reforms, including publicising all spending by lawmakers and their political groups.

Last autumn, he conducted massive and repeated yen-selling interventions to lower the soaring value of the Japanese currency that hurt the export sector, Japan's main economic engine.

His oratorical skills on the campaign trail are well known among Japan’s political community. He is a judo black-belt.

Yukio Edano, 47:

Chief Cabinet secretary Edano is Japan;s top government spokesman and rose to prominence in and beyond Japan in the weeks after March 11, giving several daily televised briefings on the ongoing Fukushima nuclear crisis.

His tireless work and calm manner won Edano, then dressed in a blue workman's suit, public admiration and lavish praise on micro-blogging site Twitter, making him a folk hero of sorts.

Despite his policy knowledge and political skills, his relative youth is considered a risk in the Japanese political world.

Yoshito Sengoku, 65:

Edano’s predecessor and now his deputy, Sengoku is a party veteran who was nicknamed Kan's “shadow Prime Minister” while he served as a chief cabinet secretary, a post he was forced to quit in January.

A lawyer by profession and one-time Socialist Party member who has held several key DPJ positions including policy chief, Sengoku enjoys an “elder brother” status within the party.

He has advocated closer ties with China and other Asian countries, and has pushed for market reforms, fiscal austerity and clean politics.

He was forced out after a censure motion by the opposition Liberal Democratic Party over his handling of the China spat in 2010.

Despite the animosity, he has managed to forge close ties with senior members of the LDP and is now reportedly leading talks to explore the idea of a post-March 11 grand coalition government between the major parties.