The play of Gin Rummy consists of two parts; the draw and the discard. The draw is made by either taking the up card or the top card on the discard pile and placing it among the cards in one’s hand, or by taking the top card of the stock and raising any part of it from the table.
The non-dealer who was dealt 11 cards rather than 10 begins the play of the hand by discarding one card face up. This is then known as the discard or “waste” pile. If he chooses, before making his first discard he can declare Gin or knock if he is in a position to do so. If the player does not knock or declare Gin, the dealer then has the choice of either picking up the card that was discarded or selecting the top card of the stock which are the cards that are face down.
If at any time during the play the player picks up his opponent’s discard, they may not discard that card on the same play. He can discard it on a subsequent hand of play. The player can pick up the opponents discard to make his hand better, either through a meld, or a combination, to knock, or just to reduce his hand. The only card that is available to be picked up is the top card. The other cards in the discard pile are considered to be dead and neither player may look at or pick up any cards other than the top card that is showing.
After the player has picked the top card from the stock or the top card from the discard pile, he then either knocks, declares Gin, or discards himself. The turn of play is now completed. Each person waits for the completion of their opponents play before they can make their next play. It goes back and forth until one person finally knocks or declares Gin. If the person is knocking then he must declare he is knocking and then discard their final card. It automatically ends that particular hand play.
It is good to note that at any point in play, either player can remove the unused stock from the table and spread the stock and count the cards that are left. This can be done as often as the player desires, but it is not usually done until the stock cards are almost depleted. This means that there are usually 12 or less cards. This is when the number of picks becomes an important factor in the actual play of the hand.
If you are not using a knock deck, then the non-dealer has the first option of selecting the turned up card that is also being used as the knock card. He can then discard another in its place, but the knock amount will not change even if the card is not there. It is at this point that you should write down the knock amount to make sure there is no dispute as to what it was, in case it is picked up.