Updated: Dec 7, 2021
If you asked a non-poker player what they thought bluffing was, they would tell you that you take a bad hand and pretend it's a good one. They would also think that this is a huge part of the game and that you will be bluffing all of the time.
While this information isn't overtly wrong, it's not quite accurate. You are taking your worst hands and turning them into bluffs, and you should be bluffing often. However, to be a profitable player you must be doing this with hands that are most likely to succeed as bluffs. Or, out of the hand combinations you could choose, the hand is so unlikely to win at showdown that it is slightly more profitable to be turned into a bluff.
The truth is bluffing is a balancing act. You need your value hands and your bluffs to be at a perfect ratio to ensure that you can't be exploited by your opponent and to maximise profitability with your worst hands that wouldn't win the pot any other way.
Your best bluffs on the river will likely be good for a number of reasons. They have very little showdown value i.e. they will be your worst hands, they block your opponents best hands on the river, or they unblock the folding range of your opponent.
By the river your hand will either win at showdown or it won't, with no more cards to see any semi-bluffs you had on the flop or turn will have either come in or missed. The same can be said for your opponent. To make a good bluff on the river you need to seriously consider how much showdown value your hand has against your opponents range. This will change depending on the board texture and the action that's taken place throughout the hand.
If you bet the flop and the turn, your opponents range will be stronger and narrower. If you haven't bet at all then villains range will be wider and therefore weaker. When your opponents range is wider, the relative value of your weaker hands is higher, as there is a greater chance that your hand will beat theirs at showdown. When you've narrowed their range down by betting, the relative strength of your hand will be decreased.
On a draw heavy board texture (a board that contains multiple straight draws and/or flush draws), your opponents range has a higher quantity of draws compared to their range on a dry board. Depending on the river card, this could mean their range is weaker overall as it will contain several missed draws. When your opponents range is wider and weaker, this will increase the relative hand strength of your hand.
Pay attention to how the action and board texture will have changed your opponents range by the river.
Why is relative hand strength important?
Knowing your relative hand strength is essentially a way of saying what your equity (% chance to win) is likely to be in the hand. If your hand is relatively strong against your opponents range, you are more likely to win at showdown and therefore you don't need to turn your hand into a bluff!
Take and A-High flush draw for example. If your draw doesn't get there on the river, it's quite possible that your opponent was on a worse draw than your own. This is why you will rarely see good players bluffing the river with A-high, it has enough showdown value to win sometimes, and we will likely have better bluffs to choose from.
Remember that bluffing is a balancing act, and when we have the choice between picking A high vs 5 high to bluff with, 5 high is much better as it is essentially guaranteed not to win at showdown. We can't bluff with everything, so one