Einwerfen or Zählspiel is a German 8-card point-trick game for four players in two teams of two and using a 32-card German-suited pack.
Any card may be led to a trick, subsequent players must follow suit if they can but are otherwise completely free in what they play.
At the beginning of such a game players draw card for being eldest hand (König) for every one of the 48 deals.
The seating arrangement changes every 16 deals, as eldest hand's partner changes so that each of the three remaining players has that role once.
[5] Einwerfen refers to the 'throwing in' i.e. smearing of valuable cards into tricks (likely to be) won by one's partner.