Play Rummy with only one deck of cards if there are less number of players. But you need more cards when more players are playing the game. When that happens, two decks of cards are used to play the game. The more the number of cards available, the more interesting the game gets because the chances of making a valid declaration become more challenging.
It depends on the Rummy variation you are playing. If you play 13-card Rummy, each player starts with 13 cards. Throughout the game, players must maintain a hand of 13 cards. The other type is the 21-card Rummy, where all the primary rules remain the same apart from the fact that each player has 21 cards, and they play with 21 cards until the end of the game.
There are multiple types of Rummy available in the market. Some are popular, but some have remained lesser known. Whatever the type is, some fundamental rules are the same in each type. Types of Rummy games are pool Rummy, point Rummy, 13 cards Rummy, 21 cards Rummy, gin Rummy, deals Rummy, Indian Rummy, Rummykubh, 500 Rummy, Contract Rummy, Oklahoma Rummy, Shanghai Rummy, canasta, kalooki Rummy, and dummy Rummy.
Even though the basic rules and regulations in both types of Rummy remain the same, some differences are there between the two. In the case of 13 cards Rummy, only 13 cards are dealt to the players, whereas in 21 cards Rummy, 21 cards are there with the players.
13-card Rummy only requires you to make at least one pure sequence. On the other hand, 21 cards Rummy requires the players to create at least three pure sequences. The point system in 13 cards and 21 cards Rummy is also different. In the first case, if you drop out before you have even played a hand, the point scored is half of the normal, and if you drop after playing a hand, it increases the point. In the second type, if you drop before playing a hand, your penalty point is 30, but if you drop after playing a hand, your penalty point is 75. The number of jokers used in the case of 13 cards Rummy includes the printed and the wild joker. But in 21 cards Rummy, there are three types of jokers. So, if 4 of Hearts is the wild joker in the game, it will have an upper joker, which in this case will be 5 of Hearts, and a lower joker, which here will be 3 of Hearts.
The value of an Ace in a Rummy is 10 points, and the value of a joker in a Rummy is 0 points. Remember, Ace is a high-value card in Rummy. Thus, if you fail to form a sequence or set with it, try discarding it.