In games with multiple betting rounds, to bluff on one round with an inferior hand that might become a much better one by chance in a later round is often called a semi-bluff. For example, a player in a stud poker game with four spade-suited cards showing (but none among his downcards) on the penultimate round might raise, hoping that others believe he has a flush even though he doesn't. If his bluff fails and he is called, he still might be dealt a spade on the final card and win the showdown (or he might be dealt another non-spade and try his bluff again, in which case it is a pure bluff on the final round rather than a semi-bluff).
The bluff is an important part of the strategy[?] of any poker game, though it will come into play more in some games than in others.
Don't be predictable. If you always bluff in certain situations, your opponents will figure this out and start calling more. If you never bluff, they'll figure that out too and stop calling your non-bluff bets (which is a bad thing--even though you might win the hand, you will fail to win the amount of their call). The exact ideal bluffing frequency in each game situation is a complicated exercise in Game theory[?] that you won't be able to solve at the table, so you may have to rely on rules of thumb, prior analysis, experience, and intuition. It also helps to have a randomizing device: for example, if your analysis or experience leads you to believe that you should bluff half of the time in a certain situation, use a device such as the color of the last card dealt, or the second hand on your watch, to make the choice.
Bluffs are more successful with fewer people in the pot. Against only one or two opponents, your chances are good that no one has a hand good enough to call. Against three or more opponents, at least one of them probably does, so bluffing is unlikely to succeed. There is also social pressure to "play sheriff": if three people act behind you, and the first two fold to your bluff, the last player will feel more obligated to call because the others will complain if he doesn't. If you have only one opponent, he won't have that problem.
Bluff much less in High-low split games--some very weak hands will call hoping for half the pot. In some games such as Omaha high-low, you would not be giving up much advantage if you never bluffed at all.
Opponents will call or fold to a bluff based on their own hands more than based on their perception of yours (even though this is not correct strategy). For example, if you are playing Seven-card stud and are dealt an upcard that makes it look as though you may have a flush (or some other "scare card"), bluffing against someone who you think has three of a kind will likely fail, because that's a strong hand for the game and a player is unlikely to fold it even if he suspects it won't win. But bluffing against someone who probably has only a small pair is more likely to be successful, even if you have nothing that looks threatening about your own cards.
In games with many betting rounds, bluff in early rounds rather than late ones. Once other players have put a lot of money into the pot, they are less likely to give up (this tendency goes beyond the correct strategy of calling more with larger pots). One good play in such games is to "semi-bluff": betting a hand in an early round that probably isn't the best, but that might become the best with a lucky future card. This play can win when either the bluff or the draw is successful.
On the last betting round, if you have a hand that might be good but that isn't very strong, you're probably better off checking and then calling a bet by your opponent rather than bluffing. A player with a worse hand will probably not call if you bet, but your check might induce him to bluff, allowing your call to win more money. A player with a better hand than yours will almost certainly call, and may raise. You also don't need the protection of a bet. Value bet your strong hands, bluff with hands you're almost sure can't win any other way, and check the ones in between.
A raise, and especially a Check-raise, as a bluff is more psychologically intimidating than just opening. Of course it also risks more of your money and makes the pot bigger (and therefore more likely to be called), so it must be used with care.