@ives @FediTips

You get a ballot with two columns. Left hand is the first vote, right hand is the second vote.

The first vote is for a *person* associated with a *party*, which differs per voting district. The person with the most votes in that district gets a seat (or used to, see below). In any case, the first votes are only summarized up to the district level, then the winning candidate is chosen.

The second vote is for a *party*. The second votes are summarized across the entire country. The second vote determines the ratio of seats the parties get.

Before the last change of mechanics between 2021 and today, all candidates chosen via the first vote would get in unconditionally. That caused caused the parliament to get insanely large because the share of parties as determined by the second vote still had to be upheld. Example: if the target size of parliament was 500 and a party got 20%, but 110 candidates were elected via first vote, they would get 10 extra seats, which would then cause 40 extra seats to be distributed among the other parties to ensure the correct ratio (I hope I didn't make maths mistake here).

That led to an insanely large parliament in the past, so it was changed so that extra directly elected candidates would not get into the parliament (the ranking of candidates which get in is based on number of votes, IIRC).

Wikipedia has more details https://en.wikipedia.org/wiki/Bundestag#Election_system_(since_2023)

And to elaborate on how that relates to what I wrote earlier: If a party has less than 5% share of second votes, it is barred from entering parliament, *unless* it has at least three directly elected candidates. So the first vote can be used to get a party in which would barely fail due to the 5% hurdle, but only if people coordinate in a district (because there it's winner-takes-all). The second vote is thus usually wasted on smaller parties and that only benefits the largest parties.