Blind vs Blind Strategy: How to Isolate Limps From the Big Blind

Blind vs blind pots are one of the most frequent and most misplayed spots in tournament poker. When the action folds to the small blind and they limp, the big blind faces a decision that most players get wrong. They either check back too often, giving the small blind a free flop with a wide range, or they isolate with the wrong hands and run headfirst into a limp reraise.

The correct strategy is more nuanced than either of those approaches, and it starts with understanding why the small blind limps in the first place.

Why the small blind limps first in

The small blind limps first in with a very wide range when it is folded to them. This is not a weak play. It is a play dictated by the incredible odds the small blind has on completing. For a look at how the small blind should construct its entire entering range across multiple stack depths, check out our guide to small blind vs big blind strategy with apestyles.

An unfortunate reality from the perspective of the small blind however is that the small blind is out of position for the entire hand. Raising builds a bigger pot that the SB then has to navigate from the worst seat at the table. By limping, the SB keeps the pot small while still getting to see a flop with a wide variety of hands.

But the SB limping range is not just weak hands hoping to see a cheap flop. It includes strong hands as well, and that is what makes isolating from the big blind so interesting. The SB has a natural incentive to limp reraise when facing an isolation raise as a means of reducing the BB’s positional advantage. By trapping with strong hands in the limping range, the SB can destroy the BB’s positional advantage by bloating the pot preflop and reducing the stack to pot ratio.

This limp reraise threat is the single most important factor in determining how the big blind should respond.

Why the big blind isolates with a polar range

Because the small blind can limp reraise and this is a core component of the structure of the scenario, the big blind can anticipate this response and shape its isolation strategy accordingly. The answer is a polar range.

A polar range consists of very strong hands and very weak hands, with fewer medium-strength hands in between. This structure directly counters the limp reraise. Here is why.

Strong hands (premium pairs, strong aces, suited broadway, etc) welcome the limp reraise. When the SB limp 3-bets, these hands are happy to continue, either by calling or 4-betting.

Weak hands (low offsuit hands like 72o, 83o, 95o, etc) are included to apply pressure and deny the SB a free flop. If the SB limp reraises, these hands simply fold. The EV lost from folding is minimal because they had very little equity in the pot after the flop given the characteristics of polar trash.

Medium-strength hands are the ones that suffer most facing limp shove. Hands in the middle of the range, such as KTo or QJo, are too strong to comfortably fold facing a limp reraise but too weak to continue profitably. By keeping these hands out of the isolation range and instead checking them back, the BB avoids the awkward spot entirely.

This is the core principle: polar ranges blunt reraise strategies. When your opponent can trap and reraise you, you counter by making your range easy to play against that action. You either have it or you do not care about folding.

How the BB isolation range changes by stack depth

The isolation range is not identical across stacks but it is always similar. Let us look at the solver output at three key stack depths to see how the big blind should isolate against a small blind limp.

10bb: tight and polar

At 10bb the stacks are so shallow that a limp reraise from the SB is almost always an all-in, and the BB cannot afford to put chips in with high equity hands that fold to a shove. The range is built around hands that either welcome the all-in or can profitably fold without losing too much (weak off suit hands that were raising to steal). One caveat here is not to lose sight of just how far down the BB is willing to isolate and call a shove. All of the suited hands being used to isolate the SB are calling a shove.

Weak suited hands are noticeably absent from much of this range. At 10bb, a limp shove from the SB is a common response, and suited hands like 76s or 54s simply cannot call a shove profitably despite their playability. The solver shows a very strong aversion to isolation with suited hands that will have to fold to a limp shove, because the combination of raising and then folding wastes both chips and equity that the BB cannot afford to lose at this stack depth.

25bb: the polar structure becomes clearer

At 25bb the BB loses much of it’s iso shoving range and is mostly limited to a non-all-in iso. The BB is still well within range of a SB limp shove and as a result maintains a strong aversion to isolating suited hands. The primary characteristic of the strategy we’re discussing, isolating polar and checking the middle of the range, is still intact.

50bb: suited hands finally enter the range

At 50bb, the dynamic shifts again. The stacks are now deep enough that the SB’s limp reraise is rarely an all-in. This changes everything for suited hands.

When the SB limp 3-bets to a non-all-in size, suited hands can call and play a postflop pot in position. Hands like 54s, 76s, and 87s now have the implied odds and playability to justify entering the isolation range. They can flop draws, make disguised hands, and leverage their position to realize equity across multiple streets.

The 50bb isolation strategy is the first depth where suited hands enter the picture at all. The polar structure is still present, but the gap in the middle of the range narrows because medium-strength suited hands can now defend against the limp reraise rather than being forced to fold.

Why suited hands have a hard time entering the range

This is the part of blind vs blind strategy that most players get wrong. People underestimate how disastrous it is to isolate and fold vs a limp shove with high quality suited hands that had the opportunity to simply check.

The issue is the limp shove. When the SB limp shoves, you need to decide: call or fold. Suited hands like 87s or 65s have decent equity against a shove range, but not enough to call profitably at 10bb or 15bb. They end up in an awkward position where they are too good to ignore but too weak to commit with.

Offsuit junk hands do not have this problem. When you isolate with J4o and the SB shoves, you fold without a second thought. The hand was never meant to play a big pot. It was there to apply pressure and collect the dead money. The iso-fold cost is minimal.

This is why we should construct our range the way we have discussed so far. The weak end of the polar range is designed to be disposable. Suited hands have too much equity to be truly disposable, so they sit in a no man’s land where isolating with them squanders valuable equity in the pot that we simply cannot afford to lose.

As stacks get deeper and the limp reraise shifts from all-in shoves to smaller 3-bets, this problem disappears. Suited hands can now call the 3-bet, see a flop, and use their playability to realize equity. That is why you see them squeak their way into the range at 50bb but barely appear at 10bb.

How to study BB isolation ranges

The best way to drill this concept is to compare isolation ranges side by side at different stack depths. BBZ Poker’s preflop charts include solved blind vs blind ranges for every stack depth, including the specific isolation ranges against SB limps.

Start at 10bb and note which hands isolate. Then move to 25bb and see what gets added. Then go to 50bb and watch the suited hands enter. The progression tells the entire story of why polar ranges work and how stack depth reshapes the strategy. The only thing you’re missing now is how to play these scenarios post flop, for that read our Complete Guide to BvB Play in MTTs.

The GTO Trainer is especially useful here. Set up the blind vs blind scenario, practice isolating against limps at different stack depths, and build the pattern recognition that makes this second nature at the table.

If you want to go even deeper on blind vs blind dynamics and build a complete system for every major spot in tournament poker, Simple Poker Systems covers isolation strategy, c-betting, river decisions, and more in 12 plug-and-play frameworks you can use at the table immediately.

Related articles

• What Are Poker Ranges and How Do You Assign Them?
• 3-Bet vs Call: Why Flatting Wide Preflop Costs You Money
• 3 Common Pre-Flop Mistakes That Poker Charts Can Fix
• How to Play the Bubble in Poker Tournaments