Isolating Limpers in Poker


An open limp is when a player who has the option to be the first to enter a pot does so by wagering the minimum bet. This is known as a limp rather than a raise. Isolating the limper is the term for raising a preflop limper(s) in order to take the initiative and play against a seemingly weak poker player.

A lot of people without much NL Hold'em experience will not isolate players frequently enough. Conversely, some regulars take this concept too far and isolate with far too many hands, or simply in spots which are poorly chosen for doing so.

You can potentially isolate with a lot of hands, depending on the table conditions. In the following article, you will learn which hands to isolate limpers with, and which hands to rather over-limp with (limping behind a previous limper). We'll also consider what sizing is going to be optimal for an isolation raise. Finally, we'll consider game dynamics which affect isolation bets.

Isolating limpers in poker

Who are the limpers?

The players who open limp tend to be the weak players. They will usually have a large VPIP and a low preflop raise percent. These players are more likely to be passive. This is where the profitability of isolating limpers comes in. The profit from isolating comes from when the other players fold and the fishy limper calls.

Not only will you usually have a positional advantage on your opponent, they will be playing fit or fold on the flop, meaning that every time they miss the flop (about 2/3rds of the time) they will fold to your continuation bet. In essence, you are building a pot and creating dead money so that you can take it away on the flop. These players will also play their hands very face up (meaning to play in a way which reveals the strength of their hand in an obvious manner) usually giving you further chances to take away the pot on the turn and river when good barrel cards come.

Isolation raise sizing

As a standard, I would recommend adding 1 big blind per limper to your usual opening sizing which should (when deeper stacked) be 3 big blinds. You can also get away with varying this slightly as stack depth/player tendencies change, and adding 0.75bbs per limper is, for example, also fine. When you are out of position it is recommendable that you go slightly larger, so using 4bbs + 1bb per limper is a good adjustment.

For example, a player has open limped and another has limped behind. The action comes around to you sitting in the small blind with AJo. A raise to 6 big blinds is good here. Anywhere between 5.5bbs to 6.5bbs is also fine. On the button with the same hand, a raise to around 5 big blinds is decent.

By raising larger out of position you accomplish several things. Firstly, you increase the amount of fold equity you are creating with your raise. You will take the flop heads-up more frequently, which is good for capturing your equity post-flop. You will also take down the pot pre-flop more frequently.

In addition, you create more scenarios where opponents will make a mistake since you put more pressure on a larger % of their range. In simple terms, this means that some marginal calls vs. a 5bb raise become folds vs. a 6bb raise, and villains may either call too light, making equity investment mistakes, or even over-fold with too many combinations.

Types of hands to isolate

We are primarily isolating for value, to play a bigger pot vs. a weaker opponent, preferably in a heads-up pot to the flop and frequently in position. Hands which are our first choices for this play with therefore include all premiums, all big pairs and big Ax holdings, broadway holdings, and some stronger suited connectors and suited gappers.

Versus a confirmed serial limper (someone who open limps frequently) and isolating from the button it's certainly fine to isolate raise all suited aces, offsuit aces down to A8o or A5o, all broadway including offsuit combos, all pairs down to 55 and suited connectors down to 78s as well as gappers such as T8s. The weaker your opponent and the more they are inclined to play weak-tight, fit or fold poker post-flop, the wider and trashier you can go with this range.

Isolating limpers with strong hands like Ace-King

Limping Behind or Over-limping

Limping behind with two-two

If you have a hand in an isolation spot which you feel is somewhat marginal for an isolation play, it's best to first consider whether it then becomes better to fold it or to limp it behind.

Hands which perform well limping behind are hands that can capture their equity post-flop even in multi-way pots, for example, hands which will either hit a monster, a monster draw, or a weak pair which we can easily get away from without further investment. Hands such as 45s, or 22. The former performs fine in multiway pots. The latter doesn't perform as well post-flop, but it's also a hand which is easy to get away from if we don't flop a set, and also doesn't lend itself well to isolating, as it rarely improves to the flop (and has no blocker).

A hand like A2o performs terribly as an over-limp, as it is so hard to know where we stand post-flop even when we connect.

Game dynamics

At low stakes, you will frequently be able to get away with isolating a lot. As you move up, you will have to hold back on isolating the limpers because you will frequently start getting exploited by good players.

- LuckyLuke

Good aggressive players will notice you are isolating a wide range of hands in position and start 3-betting you with a wide range of hands as a bluff and wider for value. In essence, you are creating even more dead money for them to try and steal. Simply tighten up a little bit facing this kind of action so your range becomes stronger.

After a while, these players should notice that you are getting out of line less often and your credibility will go up again. Target your isolation plays more frequently against weaker opponents, who will form the majority of open limpers anyway

Red Flags for Tournament Limping Traps

This comes up most frequently in tournament play, where stacks are shorter and limping as a trap is more common at such stack depths. There's a simple three-part system you can use to identify the likelihood of an open limp being a trap play with a premium holding.

Firstly, has the player never limped previously? This is an immediate red flag. Secondly, are they limping in early position? Finally, are they limping with a short stack, say 10-20 big blinds? If they fulfil two or more of these three criteria, it's likely they have a trap-heavy range for open limping in that spot, so take care! You can either limp behind with more of your range or be prepared to isolate/fold to a shove with a very high frequency. Tightening up your isolating range is certainly a must in this kind of spot.

If you've seen someone open limp more than once previously, and their stack size is still similar to those observed spots, you can assume a very low frequency of traps.

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