Toepen

Deal four cards to each player without any trump suit being set.

The first player leads a card, and each following player must follow suit if able, or play any card if not, with the highest card of the suit led winning the trick.

At any point on their turn, a player may knock on the table, called "toepen," to raise the stakes for the hand.

Other players must respond to a knock by either folding out of the hand, accepting the higher stake and continuing, or knocking again to raise further.

After four tricks are played, or all but one player has folded, the players remaining compare tricks won, and whoever has won the fewest tricks pays the current stake in chips.