Introduction to bluffing
In poker, as in any game, you want to maximize your chances of winning. In this game, you can win either by having the best hand at showdown, or by your opponent folding. That makes for two ways to win, one of which is considered passive, and one of which is considered aggressive.
Winning by showdown is considered passive, because you ultimately reach showdown by either checking or calling a bet, as opposed to winning by your opponent folding, which can only happen through an aggressive action such as betting or raising.
To a certain degree, you would naturally win by both methods, because when you have a good hand, you want to bet or raise to win more money. If you have the nuts (the best possible hand), you would naturally not want to just call or check (barring exceptions), since that could very well leave money on the table. However, imagine a case where you have a bad hand, like a busted straight draw. This hand probably will not win at showdown, but you would obviously still prefer to win, and this is where I would like to introduce the concept of bluffing.
Bluffing is when you chuck out a bet or raise with a hand that you assume would not win at showdown, making a bet the only winning option.
As you can tell, we missed our straight draw. Very sad… What can we do about that? Assuming that you have been following along, we can bluff. Bet to try and scare our opponent away. If we do not bluff, we will likely lose. A relatively good rule of thumb is that you want to bluff with some of your worst hands on the river. Jack high, as we have in this scenario, would definitely constitute one of our worst possible hands. This is because most other hands will have made at least a pair, or simply be queen, king or ace high, compared to jack high.
Bluffing can increase our chances of winning.
If our opponent has or they may be folding to a bet on the river. Successful bluffs take into account how the action has played out, what hands your opponent is likely to have and how they will react to a bet and a lot more (when you become advanced).
Often when you are bluffing before the river you want to have a hand that has a chance to improve to become the best. This is called semi-bluffing and is most often done with flush draws and straight draws. In the example above we have a straight draw which gives us a decent chance of improving to a strong hand. Before the river it is recommended to bluff more frequently with hands with a good chance of improving.
To summarize, we bluff in order to secure ourselves an extra chance to win. You cannot master poker without mastering how to bluff and when. The best you can hope for without this element of the game is picking pennies from poor players who lose way too often at showdown.