It’s a generalisation, but usually a correct one, that good players don’t make small bets (by small bets we mean less than half the size of the pot). Small bets aren’t often used because they don’t make opponents fold better hands, they don’t extract maximum value when you’re winning and they give other players too cheap a price to draw to a better hand. However, like everything in poker there are situations where they can be used to good effect.
One use of smaller bets is to extract value in spots where you’re sure an opponent has a weak hand and you’re comfortably winning the hand. If you make a normal-sized bet you will always get a fold, but they may pay off a small bet out of curiosity. Let’s say you’ve had the lead in a hand, which you’ve been semi-bluffing with a flush draw and your opponent has been calling. On the river the flush arrives and your opponent checks again. If it’s an opponent who plays their marginal hands weakly this way and almost never has a big hand in this spot, you may make the most money by making a small value bet to make him curious with a one or even two-pair hand. It’s important not to overdo this though, because you only need one big bet to be called to equal many of these smaller bets being paid off.
Defensive bets
You can also use small bets as defensive or blocking bets. These can be used either to set the price of continuing when you have a drawing hand (hopefully stopping your opponent from charging too high a price with a bet size of his choosing), or to prevent yourself being bluffed off a winning hand on the river if you check. Blocking bets are a great tool against weaker players but stronger players will often attack them, putting you in some very difficult spots.
Another reason for using small bets is to reopen the action in an attempt to induce errors from your opponents. For example, you’ve called a three-bet from an aggressive opponent who is in the big blind when you raised on the button with Aces. The flop is 4d-5c-8h and your opponent bets. You have several options here and often the best line is to make a normal raise. However another option is to make a small bet in the form of a minimum raise. If he’s an okay aggressive player this will often encourage him to shove in this spot with a variety of losing hands, thinking your min-raise bet is weak.
Read part I
Read part III