Gin Rummy is a card game of draws and discards which may be played by either two or four players. You can play this game and other online rummy games at Rummy Royal, the top internet rummy room.  The ultimate objective is to be first player to rid yourself of all the cards in your hand by compiling them into sets or sequences. The secondary objective is to minimize the number of cards in your hand that cannot be placed into a set or sequence. One regular deck of 52 cards (excluding jokers) is used to play the game of gin rummy, and every card in the deck is assigned a point value. The lowest value is the Ace card, which is valued at one point. Then the numbered cards from two through ten are worth their individual face value. So, for example, a four card is valued at four points, the nine card is worth nine, etc. The face cards, which are the Jack, Queen, and King, have the highest value at ten points each. These values will become important in the scoring process, so a paper and pencil will be handy for tallying the scores. In order to understand the rules of Gin Rummy, first there are a few terms to learn.
 

“Meld”

A Meld is either a “Set” of three to four cards that share the same face value (such as three 4s), or it is a sequential “Run” of three cards or greater in a row, each being of identical suits. In order for a Run to count as a Meld, all of the cards in the sequence must be of the same matching suit (such as hearts).
 

“Deadwood”

“Deadwood” cards are the cards which remain unusable, and which cannot be melded into any of the runs and/or sets available either on the table or in the player’s hand. Gin Rummy rules state that the goal is to eliminate as much deadwood from the player's hand as possible.
 
In a two-player game, players are each dealt ten cards to start. If there are three or four players, each receives seven cards. When all players have received their starting hand, the remaining cards in the deck are placed face down (called the Stock pile). In every turn, each player must draw one card (from either the Stock pile or from the pile of discarded cards), and then they must also discard one card.

"Gin", "Knock" and "Undercut"

Gin Rummy rules provide three ways of winning the game. These are “Gin”, “Knock”, and “Undercut”.  Going Gin means that you have managed to get all of your cards into melds with no remaining deadwood. Going Gin awards extra bonus points in the final scoring tally. Knocking does usually mean to knock or tap on the playing table. If the majority of the cards in your hand are in a meld, and the scoring value of your deadwood cards is less than ten points, you may knock to stop the play and start tallying. The score is derived from subtracting the knocker’s deadwoods from the sum of the opponent’s deadwoods. An Undercut win is achieved when your opponent knocks and lays down their cards. You may then try to reduce or eliminate your own deadwood count by adding to the melds that the knocker has lain down. If you can lay down enough cards to reduce your deadwood score to a lower number than the knocker’s deadwood score, you have achieved an Undercut win, and the knocker is assessed an additional 25-point penalty to their deadwood total.  If the stock pile of cards is depleted during play, Gin Rummy rules permit the dealer to take the pile of discarded cards, reshuffle them and form a new deck.