Black Jack at 21.
The deck is stripped of jokers, using 52 cards. Initially, each person is dealt two cards, one face-up and one face-down. They can choose to hit for more cards, skip, or stand to decide the outcome; the one closest to a total of 21 points wins, and anything over 21 is a bust. Face cards J, Q, K are counted as 10, while an Ace can be 1 or 11, as needed.
Those are the basic rules of Black Jack. As the game spread, various original rules were also incorporated in different regions.
The Black Jack that Li Lin and Ji Ai'er were playing had their own unique set of rules.
Three new rules were introduced.
1. There is no dealer; both players play as opponents;
2. The game is decided in a single round of five matches;
3. No hole cards are dealt;
"Is there anything else you're unclear about?"
"Who will deal the cards? Whichever side it is, it's pretty much telling the other side 'go ahead and cheat.'"