Poker Strategy

A big mistake players sometimes make is checking with a weak hand in Holdem before the river when it is assumed that they have the winner while they also realize that many river cards are "scare cards".

For example, you have 76 in the big blind. A player in late position raises and you call, defending your blind when you don't figure the raiser to have much. The flop is 873 giving you middle pair. Note that this is a good flop for you and you are probably ahead right now. Still, you decide to check to the raiser and just call. The turn is a three pairing the board. This a great turn card for you because it almost certainly did not help your opponent. What should you do now?

Many players continue with the strategy of "check, call"; they expect the aggressor to bet again and they intend to call him down figuring that he's got high cards and the sevens are good. However, this is a mistake! Your opponent might realize that you have possibly caught a pair on the flop after you called his bet on the flop and he will therefore not bet the turn giving himself a "free river card". This river card may turn out to be disastrous to you if your opponent indeed has six outs and catches one of them. Not only will you lose the pot on the river when this was avoidable but you will also lose the river bet, if you decide to call him down just in case he's bluffing (as you would usually do).

The general rule in Holdem is simple: Don't give free cards when it is apparent that you're ahead and you have a vulnerable hand. You can give a free card when it's not obvious that you're ahead and you can give a free card when you have a more sturdier hand, such as two pair but you can't afford to give a free card when you know you're ahead AND you are vulnerable.

Trying to check raise the turn is probably a mistake because your opponent might not bet. Also, your hand is not strong enough and you would rather that your opponent fold to your turn bet than getting him to CORRECTLY call your check-raise if he has six outs. Lastly, if you get fancy and check-raise, he might get fancy with you and raise you again, putting you in a very difficult spot where you will usually be forced to fold.

If you bet out on the turn and get raised, you are usually behind -way behind- since it is rare that a player will invest two big bets on the turn in that spot with no pair. If he's got an overpair then you are now drawing to a seven for a two-outer and you should fold. On the other hand, if he doesn't have a pair, your bet on the turn puts pressure on him to fold his overs or his ace-high and you should be happy to win the pot right there. Note also that if your opponent is calling you with a flush draw then your hand is slightly better now that the board is paired up because the flush might give you a full house. Thus when you flop a pair (or better pairwise) then a pair on turn almost ALWAYS helps your hand. It might help your opponent even more but assuming that you had the best hand on the flop, the pair on the turn now preserves that status quo and now is the time to take the lead in betting if you hadn't taken the lead already.

AKo vs 76o in the BB in a 20-40 Limit HE game: Odds of winning when played straightforward
	preflop
	61.5% Note: A raise in position is correct.	22.1% Note: A bet is incorrect but a call of $20 to win $90 is correct (18.2% is break- even).	13.6% Note: A call of $40 to try to win the $170 pot is no longer correct with only one card to come (break-even is 19%).
	38.5% Note: There is $70 in the pot, making a $20 call correct (22.2% is the break-even point).	77.9% Note: Since your opponent will probably correctly call your bet anyway, it's not a big mistake to just check-call. If you check-raise here your opponent is surely correct to call.	86.4% Note: Since your opponent is wrong to call if he knew what you had, you MUST put him to the test here and force him to either correctly fold (which is fine with you) or incorrectly call if he thinks you're bluffing or or if he's not playing by the math.

As you can see from the table above, it is marginally correct for the AK to call on the flop against the 76 even if he knew what you had, since the bet is still small and there are two cards to come. Thus, by assmuning the betting intiative on the flop, you are not accomplishing much (unless your opponent is a maniac and is prone to keep raising with it on the flop or if he is supertight and will incorrectly fold the flop for just one bet). On the turn, however, your opponent is too much of an underdog to correctly call a big bet with one card to come. According to the Fundametal Theorem of Poker, you want him to incorrectly call but you also don't mind that much if he folds since the pot is so big already.

What happens if you try to check-raise your opponent on the flop or on the turn?

AKo vs 76o in the BB in a 20-40 Limit HE game: Odds of winning on the turn when playing the check-raise
	preflop
	61.5%	13.6% Note: If there has been a check-raise on the flop, there is now $170 in the pot. The AK is calling $40 on the turn to try to win $210. Break-even is 16% making this call still incorrect.	13.6% Note: If your opponent check-raises you on the turn, you are then calling $40 to try to win $250 (break -even is 13.8%) making the call just about correct.
	38.5%	86.4% Note: By check-raising the flop, you are inducing your opponent to stay in because the pot is bigger now. While it is still incorrect for your opponent to call, many players will call now that the pot is bigger and there is the slight chance that their opponent is bluffing. According to the Fundamental Theorem of Poker, you still want your opponent to incorrectly call you but not by much.	86.4% Note: Since your opponent would be correct to call your check-raise on the turn if you do so, there's no point in going for it. You'd rather just bet out and let your opponent make the mistake of calling or correctly get out of your pot.

Notice that this is a very classical study since this situation will come up very frequently in Holdem, where you will either have the two overcards or you will have the small pair. As you can see, if you are the one with the small pair, it is vital that you bet the turn when there is only one card to come and the bets are doubled. Check-raising the turn is a gamble: it'll make you more money when your hand holds up but it doesn't yield any equity. You only gain equity in poker when your opponent is in violation of the Fundamental Theorem of Poker. Furthermore, if you check the turn and your opponent checks behind you, you have allowed a disaster to occur: you gave your opponent a free card to potentially beat you in a situation where you could have forced him to make a mistake and call you as a big underdog to try to win.