Don't know your Bundestag from your Bavaria? Our guide will tell you all you need to know ahead of this key European vote.

Aubrey Allegretti, Political Reporter

All eyes are on Germany, as voters prepare to elect a new chancellor and hundreds of MPs amidst a backdrop of political surprises.

Angela Merkel is vying for a fourth term as leader of Europe's largest economy, pitching herself as the candidate of stability in Sunday's poll.

Sky News has your bluffer's guide to the candidates, parties, possible coalitions, opinion polls and how the election system works.


Image: Angela Merkel and Martin Schulz are the two candidates who could win

Who is running to be German Chancellor?

Centre-right incumbent Angela Merkel is the favourite to win the top job. She has outlasted every other western and democratically-elected European leader, and is considered the most influential voice in the EU.

Her only serious challenger is Martin Schulz, a former president of the European Parliament.

Five other parties are putting up their own candidates, excluding one that has already endorsed Mrs Merkel for the leadership.

:: Profile - Angela Merkel

:: Profile - Martin Schulz

Which parties are running in the German election?

Altogether, 38 parties will feature on at least one set of ballot papers across Germany's 16 states.

Image: Hundreds of MPs are elected to the Bundestag chamber

The main ones are listed below with their current number of seats in the chamber known as the Bundestag:

:: Christian Democratic Union (CDU) - 254

:: Social Democratic Party (SPD) - 193

:: The Left (Die Linke) - 64

:: Alliance 90/ The Greens - 63

:: Christian Social Union (CSU) - 56

:: Free Democratic Party (FDP) - 0

:: Alternative for Germany (AfD) - 0

Mrs Merkel currently runs a grand coalition government comprised of her party, the CDU and its Bavarian sister party the CSU, and Mr Schulz's SPD. It is the third of its kind since the Second World War.

:: Anti-Islam AfD on course to win first seats

How does the German party system work?

Germany operates a coalition system of government. Parties with similar political aims join together and strike deals to support each other because there is no single majority winner.

The current setup is rare because the main two opposition party groupings - the CDU/CSU and the SPD - are working together.

This is because Mrs Merkel lost her previous coalition partners, the Free Democrats, at the last election when they failed to win any seats.

All you need to know about the German election

What are the possible coalitions outcomes from the German election?

Mrs Merkel's best chance is to team up with the Greens and newly-rejuvenated Free Democrats.

The 'Jamaica coalition' - so called because of the parties' respective black, green and yellow colours - would suit the current leader best.

She could also likely get close to the majority line with the support of only either the Greens or Free Democrats, but those tight margins will be ultimately dictated by the results.

Mr Schulz's best hope is of a strong performance from the left, which could earn him enough seats to partner in a three-way coalition with the Greens.

The far-right AfD is running for the first time, and while unlikely to be included in any coalition led by the two main parties, it is on course to win its first seats.

Image: Merkel and Schulz are fighting it out for the top job but the far-right AfD is on course to win its first seats

How does the German electoral system work?

Each voter gets two votes: one for a constituency candidate and one for a party running in the region.

The first is elected under first-past-the-post - the system used in Britain to return MPs. The second is elected under a list system. Parties rank their candidates, who are elected in that order based on the number of votes received.

At least 598 MPs are elected this way - with up to 202 more also able to win seats in a top up to ensure proportional representation as closely as possible.

The leader of the largest party is then nominated by the German president - a largely ceremonial rule - to become Chancellor.

Any party must get more than 5% nationally to win a seat in the Bundestag.

Image: Opinion polls put Merkel comfortably ahead

What do the German election opinion polls tell us about a likely outcome?

Mrs Merkel seemed to win the only TV debate with Mr Schulz of the whole campaign, according to voters.

An opinion poll for public broadcaster ARD said 55% of viewers found her more convincing, while 35% were won over by the SPD leader.

Another recent poll found 80% of Germans are content economically, suggesting on one of the election's major issues she has a key advantage.

In May, the CDU/CSU and SPD were less than 3% apart in the opinion polls, but that gap has since widened to around 13%.