Overbetting the River in No-Limit Hold'em
Of course, when estimating the chances of an opponent calling when you bet big with strong hands, assessing the player’s skill level is an important factor as well, with players who have difficulty folding hands or who are “calling stations” excellent ones against whom to make such bets.
When it comes to post-flop no-limit hold'em, knowing how to size one's bets -- and how to interpret what the size of opponents' bets signify -- is an especially useful skill. Most post-flop bets are made and interpreted according to how they relate to the size of the pot, with an "overbet" generally indicating something approaching a pot-sized bet or even greater. Overbetting the river, then, can be one of the more significant bets you'll make or face in no-limit hold'em.
While inexperienced and/or unskilled players may sometimes overbet the river simply out of a lack of understanding regarding bet sizing, more savvy players can be found overbetting the river in situations where the circumstances are well suited for exploiting opponents for maximum value.
While there are variations on the theme, most instances when overbetting the river is correct essentially fulfill similar criteria, namely, (1) you are certain to have the better hand; (2) you are reasonably certain your opponent will likely call your oversized bet with a lesser hand.
One variation is when you make an especially strong hand in a situation when your opponent is likely to have made a strong hand as well and thus might be willing to call off a lot on the end. Another would be a situation in which the board is especially coordinated -- say four to a straight -- and you happen to hold the nuts (e.g., Q-J on a A-10-9-8-7 board).
Certain boards yielding multiple high hands, e.g., two pairs among the five community cards, can be instances where you might exploit an opponent with a river overbet when you hold the best possible hand and he can't bring himself to fold his strong but second-best hand. The completion of unlikely backdoor draws can also occasionally present similar opportunities.
Say you have Js-10s and are calling opponent's bets on a Ad-9d-8s flop and 2s turn, then the river brings the Ks to complete a backdoor spade flush for you.
You were drawing to a straight initially, and with two diamonds on the flop your opponent might lean toward thinking you were gunning for a third diamond with your previous calls. If he's drawn a set or two pair or some other strong hand, he may call a river overbet as it could look like an attempt to bluff after missing either the straight or diamond flush draw.
Of course, when estimating the chances of an opponent calling when you bet big with strong hands, assessing the player's skill level is an important factor as well, with players who have difficulty folding hands or who are "calling stations" excellent ones against whom to make such bets.
Against such opponents you may sometimes wish to overbet rivers when you aren't holding the nuts, but still believe the likelihood your weaker opponent has a better hand to be slim. You might raise with A-K against an opponent, flop an ace, and be certain enough he is calling you down with a lesser ace or lesser pair to make the big bet on the end and obtain even more value.
Making overbets in those spots occasionally can also help on a metagame level because they show the table your willingness to bet big on the river even without the nuts. Obviously you want to be wary about overbetting as a bluff -- and never do so against call-happy opponents -- although hands may arise where that, too, can work against certain kinds of opponents and in certain situations.
On the whole, situations calling for river overbets should be somewhat uncommon, and more often than not you'll want to be sizing bets more reasonably on the river in spots where you are hoping to get calls and obtain value. But stay mindful when opportunities present themselves in which you might bet more and thus make fifth street even more profitable.