Now that you have your hand arranged to your satisfaction, a look at your cards should indicate to you whether you have what appears to be a winning or losing hand. In this determination, you need to look closely at the knock card value.
If the knock card is high, such as an 8, 9, or 10, then the hand could be ended very quickly. This must be kept in mind when determining what kind of hand you have. If the knock card is an in-between card such as a 6 or a 7, the play of the hand will change slightly. If the knock card is a low card under 5, the strategy will chance drastically because in all likelihood you will need 9 melded cards before a knock can be declared. When the knock card is an Ace, and the game must be played to a gin, the strategy is dramatically different.
Frequently, a hand that appears to be a winning type of hand for a high knock may be a very bad hand for gin or a low knock. Keep in mind that in approximately half of gin hands the knock card will be 8 or higher, so it is best to really know your strategy when you have a higher knock card.
When the knock card is anything from a king to a nine, you can knock by melding five cards into one long sequence, but the melding of 2 three-card sets or six matched cards is more common. There are several combinations of four low cards that total 10. There are almost as many that total 9, and quite a few that total 8. While there are not as many combinations of low cards that equal 8 as there are 10, it is still wise to play for two melds and leave 4 unmatched low cards.
When the knock card is a 6 or 7, your strategy will have to change slightly since 2 three-card melds will not usually be sufficient to knock. With only 2 three-card melds your unmatched cards would have to be 3, 2, Ace, Ace if the knock card is a 7, or 2, 2, Ace, Ace, if it is a 6. Therefore unless you already have 3 of these key cards, it is best to play for seven matched cards – a four-card sequence, and a three-card run, or 3 three-card melds.
With a low card knock, it is best to plan your hand toward nine melded cards – 3 three-card sets. If you have a 4 or 5 for a knock card then it is possible to go to seven melded cards, but this is considered a freak hand, so it is best to plan for 3 three-card melds.
When the knock card is an ace, you must go gin melding all 10 cards. Since you have no choice to go gin, it is necessary to have a four-card run. This does not include freak hands when you have a five or six-card run. During regular hands, you need to play in a manner in which you will wind up with at least 2 three-card melds, and 1 four-card meld.