“Gardena Jackpots,” also called “Jacks to Open” or just “Jackpots,” refers to the set of rules that was commonly in use for Five Card Draw games in Gardena poker clubs during the 30s through 70s. The game was played with a normal deck but with a joker added as a “bug.” The bug was a kind of wild card, but it could only be used to complete flushes and straights; otherwise, it counted as an ace. There were no blinds because the players would ante instead.
The predraw action started with the player on the dealer's left, just like normal, but in order to make a bet, one had to have a pair of jacks or better. If nobody had JJ or better, then the hand ended without a winner, and a new hand began.
After the initial betting round was over, players exchanged as many cards as they wanted from their five-card hands for new ones. Whoever initiated the betting, or “opened,” might wish to break the hand that qualified for opening. In this case, he or she would save the discarded cards so as to be able to prove later on that the hand did meet the JJ or better opening requirement.
After all remaining participants drew their new cards, there followed a second round of betting and then the showdown. In order to win the pot, one had to have at least three of a kind. If nobody had a hand of that strength or greater, then the entire pot was carried over to the next hand.