Donk bluffing, betting out against an opponent who put the last bet or raise into the pot on the previous round with a hand that expects to lose a showdown, is an unusual move which can be highly profitable if executed correctly. It can also be a difficult play to pull off.
Donk bets are relatively rare in limit hold 'em. Aggressive in-position players usually have a strong hand range and can use their positional advantage to extract further profit from the hand, so "checking to the raiser" is common. The most common reason to donk on either the turn or river is when a new card comes off which significantly changes the board, improving the out-of-position player's range in comparison to the raiser's, making check-raising for value hard to successfully pull off.
For example, under-the-gun (UTG) raises in a six handed game, the small blind three-bets and everyone else folds. The flop comes 8-5-4 and UTG raises the small blind's bet. The small blind calls and an Ace comes on the turn. This is a good spot to donk out. The small blind has a relatively tight three-betting range composed of many Ace-high hands which would just call the raise on the flop, while UTG has many flopped pairs and pocket pairs which could raise this flop for value. Many of these hands are underdogs to the small blind's range on this turn and would frequently check behind; meaning that donking out is the best way for the small blind to extract value. Other examples include highly coordinated boards of low cards against a player with many high cards in their range.
If you've decided to donk some hands for value on a given river card, then balancing these with some bluffs should in theory be easy. You should choose to bluff with the very worst hands in your range, as these have the least chance to win at showdown if both players check, and they have the most to gain if the other players fold. You should then bluff as many of your worst hands so as to achieve your desired ratio of value bets to bluffs.
Things are much harder in practice. This is because you have to (quickly, so as to make your bet credible) recognize two things:
1). This is a river card you want to donk some hands in your range for value
2). Your current hand is near the bottom of your range
This can be difficult, as the standard play with weak hands is to check and call on earlier streets, while checking and folding on the river without improvement. Additionally, a river card which significantly changes the board can also significantly affect the shape of your range, Certain weak hands might see much improvement, meaning that a hand which was capable of calling down before is now at the very bottom of your range and is a candidate for donk-bluffing.
This importance of timing can't be underestimated. Your bluff will have a much better chance of succeeding if the timing is natural; an unusually large pause might make your bet seem like it is born out of desperation and not real strength.
All these factors make donk-bluffing a hard trick to pull off in the heat of the moment. Here's a hand where I missed out on a good bluffing opportunity:
Example #1
$15/$30 Limit Hold 'em – 4 players
Pre Flop: (1.5 SB) Hero is SB with Q
7
1 fold, BTN raises, Hero 3-bets, 1 fold, BTN calls
This is a standard three-bet against an aggressive button open-raiser.
Flop: (7 SB) K
9 4
(2 players)
Hero bets, BTN calls
Standard continuation bet.
Turn: (4.5 BB) 5 (2 players)
Hero checks, BTN bets, Hero calls
Here my hand might appear to be a good hand to semi-bluff, but as this is a blind steal situation my hand is unlikely to get any better hands such as ace-highs or pairs to fold. By check-calling a queen-high flush draw I can hopefully sometimes still win if my opponent checks behind on the river, and having some flush draws in my check-call range allows me to represent a made flush on the river after check-calling the turn.
River: (6.5 BB) A
(2 players)
Hero checks, BTN bets, Hero folds
My turn check-call range consists largely of ace-highs and low flopped pairs which are scared of a turn raise. My opponent's turn bet range consists mainly of pocket pairs and semi-bluffs. Ace-highs are unlikely to bet the turn as I'm capable of check-raising the turn both for value and as a semi-bluff. My opponent can hold a strong hand like A9 but due to card removal hands like these are relatively unlikely.
The differences in our ranges and the fact that Queen-high is at the absolute bottom of my range make this a great spot to donk-bluff.
Example # 2
Here's a hand where my opponent showed me how to donk-bluff correctly:
$20/$40 Limit Hold 'em – 5 players
Pre Flop: (1.5 SB) Hero is BB with 7 6, SB has A K
3 folds, SB raises, Hero calls
Flop: (4 SB) T 3 7 (2 players)
SB bets, Hero raises, SB calls
This is a good spot for me to raise the flop. Both players' hand ranges are extremely wide in this blind-versus-blind confrontation, and although my hand does well against my opponent's range, it is too vulnerable to delay my raise until a later street.
Turn: (4 BB) 8 (2 players)
SB checks, Hero bets, SB calls
Picking up a gutshot gives me enough equity to call down against a check-raise, allowing me to continue to bet for value. Many opponents would check-raise this turn with a picked up straight- or flush-draw.
River: (6 BB) 9 (2 players)
SB bets, Hero calls
Turning back to my opponent: SB's play has been standard up until now. On the flop and turn AK high can beat the many bluffs I can hold. The river card alters SB's range significantly: other possible hands are predominately weak pairs and hands which are various combinations of straight draws and high-card value. The 9 improves all straight draws, either by pairing them up or by hitting the straight. This means that AK high has been relegated in status from a bluff-catcher to the very worst hand in SB's range. In addition, it makes a lot of sense to donk-bet the river for value because there are more straights in SB's range than mine. My range consists of many hands which paired the flop – hands which will therefore only have one card left to hold a 6 or a J for a straight. Since I hold so few straights I will unable to bet that many hands for value if it's checked to me.
SB was unfortunate that I did happen to have a straight with my second hole card. With just one pair, my decision would have been very difficult and I would've been forced to fold some winning hands.
Conclusion
Successfully pulling off this play requires a lot of planning on earlier streets. Like in my hand with Q 7, you will need to be aware of times when your hand is at the bottom of your range and will remain so on plausible river donking cards. In addition, you need to realize cases like in the second example where a scary river will turn your current holding into a bluff candidate. Similar situations will occur on three-flush boards, where a fourth flush card will turn a hand like bottom- or -middle-pair into a bluff.
