Turks vote on May 14 in an election seen as one of the most consequential in Turkey's modern history, with President Tayyip Erdogan facing the biggest political challenge of his two-decade rule.
Here is a guide to the election, the presidential candidates, and the political alliances vying for power:
THE ELECTION
Turks will be electing both a president and parliament for a five-year term.
To win the presidency in the first round, a candidate must obtain more than 50% of ballots cast. If no candidate secures more than half the votes, a May 28 runoff will be held between the two leading candidates Erdogan and opposition leader Kemal Kilicdaroglu.
The powers of the presidency were broadened in 2017 when a referendum narrowly approved switching Turkey from a parliamentary to a presidential system. This abolished the post of prime minister and made the president head of government.
Voters will also elect 600 members of parliament. They are elected by party-list proportional representation in 87 districts.
Turkish elections are typically monitored by hundreds of thousands of volunteers across the country. Political parties will also have observers.
POLLING
More than 64 million Turks are eligible to vote, including more than 6 million first-time voters. There are 3.4 million voters overseas, who completed voting by May 9.
Voters in Turkey will cast ballots at 190,736 polling stations. Polls will open at 0800 a.m. (0500 GMT) and close at 0500 p.m. (1400 GMT) on May 14.
Turnout in Turkish elections is generally high. In 2018, nearly 87% of eligible voters cast ballots.
The sale of alcohol is banned on the day of the election.
RESULTS
The High Election Board (YSK) said that on election day, in line with election law, news, forecasts and commentaries about the vote are banned until 6 pm (1300 GMT).
Reports on some aspects of the election are then allowed, but media are only free to report on election results from 9 pm (1800 GMT), which will roll in from across Turkey.
The YSK may decide to lift the embargo on such reporting before 9 pm if it regards that as necessary.
By late on Sunday there could be a clear indication of the presidential election result.
THE CANDIDATES:
PRESIDENT TAYYIP ERDOGAN
More than 20 years after Erdogan and his AK Party (AKP) came to power, he hopes to extend his tenure as modern Turkey's longest serving ruler. He won in the first round in 2018 with 52.6% of the vote.
Polls currently show support roughly around 44-45%.
KEMAL KILICDAROGLU
Kilicdaroglu is the joint presidential candidate of the six-party main opposition alliance. He is chairman of the Republican People's Party (CHP), which was established by Mustafa Kemal Ataturk - the founder of modern Turkey.
Polls show his support is near the critical 50% threshold.
SINAN OGAN
Ogan was a former lawmaker with the Nationalist Movement Party (MHP), an ally of Erdogan's AK Party.
Polls currently show him lagging far behind.
POLITICAL ALLIANCES
Turkey has many political parties which have coalesced into several electoral alliances.
The main ones are:
THE PEOPLE'S ALLIANCE
The People's Alliance was formed ahead of the 2018 election by Erdogan's AKP and the MHP, and won both the presidential and parliamentary votes.
Since then, it has been joined by the New Welfare Party of Fatih Erbakan, the son of Erdogan's mentor Necmettin Erbakan, as well as the right-wing Great Unity Party.
THE NATION ALLIANCE
The main opposition bloc, the Nation Alliance backs Kilicdaroglu for president. Formed ahead of the 2018 election, it initially comprised the CHP, the center-right IYI Party, the Islamist Felicity (Saadet) Party and the Democrat Party (DP).
In 2019 municipal elections it shocked Erdogan by defeating AKP mayoral candidates in Ankara and Istanbul - a post Erdogan held in the 1990s and which his AKP had controlled for nearly two decades.
Two parties founded by former Erdogan allies later joined the alliance: the Deva (Remedy) Party formed by Ali Babacan, who left the AKP due to differences over its direction, and the Future Party of Ahmet Davutoglu, a former prime minister who was also once an AKP member.
THE LABOUR AND FREEDOM ALLIANCE
This alliance is led by the pro-Kurdish Peoples' Democratic Party (HDP), currently parliament's third biggest and seen as a potential kingmaker in the election.
The HDP is not fielding a presidential candidate and has not explicitly endorsed someone, but has said it will carry out its "responsibility against the one-man rule".
The HDP's cooperation with the opposition in the 2019 local elections helped defeat the AKP in major cities.
The Workers Party of Turkey (TIP) joined the alliance after emerging as a vocal opposition figure in the aftermath of the Feb. 6 earthquakes.
The alliance also includes the Green Left Party (YSP), under whose banner HDP candidates will run to circumvent its potential closure due to a lawsuit.
(Reporting by Azra Ceylan and Canan Sevgili; Editing by Tom Perry, Alexandra Hudson)
