Blind vs. Blind: SB vs. BB Preflop Ranges

Blind versus blind is where preflop gets hardest. It happens constantly, the ranges are the widest at the table, and the small blind is fighting positional gravity the whole way. It is also a spot a lot of chart products either simplify or skip. This guide covers why the ranges are so wide, the small blind's limp-or-raise problem, how the big blind should respond, how stack depth reshapes the fight, the leaks that cost players the most, and how cash and tournaments differ.

Why the ranges blow up

When the action folds to the small blind, only two players remain and both have already put money in. Two things follow:

• Dead money is on offer. The blinds are already in the pot, so there is something worth contesting even with a weak hand.
• No one is left to wake up. There are no players behind who can show up with a big hand, so the usual reason to play tight is gone.

Put those together and both players open up dramatically. The small blind attacks a wide range, and the big blind defends a very wide range in response. This is not loose play, it is the correct response to the incentives. A player who folds the small blind "because the hand is weak" is missing that weakness is relative: against only the big blind, a lot of weak hands are still worth playing.

The small blind's problem: position

The small blind acts first on every postflop street. That positional disadvantage is permanent and severe, and it shapes the whole strategy. A solved small blind approach usually does not pick a single action. It mixes between:

• Raising, to take the initiative and deny the big blind a free flop, and
• Completing (limping), to see a flop cheaply with hands that do not want to bloat the pot out of position.

That limp range is exactly what oversimplified charts tend to drop. Removing it makes the small blind either too weak (folding too much dead money) or too reckless (raising hands that hate being out of position in a raised pot).

Why the small blind limp exists

The limp is not a passive cop-out; it is a deliberate part of a balanced strategy. By completing, the small blind gets to play a flop cheaply with hands that have some value but do not want to build a big pot from out of position. It also protects the completing range: if the small blind only ever raised or folded, the big blind could attack the raises harder and check through more flops. A limp range that contains a mix of trap hands and speculative hands keeps the big blind honest. Whether the small blind should limp at all, and how heavily, depends on the structure, which is one more reason a generic chart can quietly mislead you here. A proper solve keeps both branches, with the frequencies that hold the strategy together.

The big blind's response

Facing a small blind open, the big blind is getting a great price and is closing the action, so it defends wide, flatting a broad, condensed range and three-betting a mix of value and bluffs to punish the small blind's positional weakness.

The three-bet construction is worth studying on its own. Because the big blind will be in position postflop, it can three-bet a linear, aggressive range for value and add bluffs that block the small blind's strong continues. The flatting range, by contrast, is condensed: lots of medium-strength hands that are happy to see a flop in position but do not want to blow up the pot. Splitting hands correctly between flat and three-bet is where most of the big blind's edge comes from, and it is exactly the kind of decision a rounded-off chart smooths over. The exact width depends on the small blind's sizing and on the structure: more three-bet-or-fold in a raked cash game, more flatting when a tournament ante is sweetening the pot.

How stack depth changes the fight

Blind versus blind does not look the same at every depth. Deep, both players have room to raise, three-bet, and play postflop, so the mixed limp and raise strategies and the three-bet wars are fully live. As stacks get shorter, the postflop game shrinks, three-bets start committing stacks, and eventually the small blind's decision compresses toward raise-or-shove while the big blind's defense tilts toward call-or-jam.

Think about it as three rough zones. Deep (say 80bb and up), the full toolbox is in play and postflop skill matters most. Medium (around 40bb to 60bb), three-bets get closer to committing and the limp range thins. Short (25bb and below), the game is mostly about jamming, calling jams, and small raise-or-shove decisions, and preflop accuracy is almost the whole story. Learning those transitions is what separates a player who knows "blind-vs-blind is wide" from one who knows what to actually do at 45bb versus 20bb.

Thinking one street ahead

Preflop blind-versus-blind decisions only make sense if you picture the flop that follows, because that is what the solve is doing. When the small blind completes, it is choosing to play a single-raised or limped pot out of position, which means it wants hands that can flop something and get away cheaply, not hands that build a big pot it then has to navigate from the wrong seat. When the big blind flats rather than three-bets, it is choosing to keep the small blind's range wide and play a pot in position, where it can realize equity comfortably. When it three-bets instead, it is choosing to bloat the pot with a hand happy to do so.

You do not need to solve the postflop tree to use this. You just need to notice that the preflop split is a postflop plan. A hand that hates playing a raised pot out of position belongs in the small blind's fold or limp branch, not its raise branch. A big-blind hand that plays great in a single-raised pot in position belongs in the flat, not the three-bet. Reading the ranges through that lens is what turns a wall of frequencies into a strategy you understand rather than memorize.

Common blind-vs-blind leaks

• Over-folding the big blind. The price is usually excellent. Folding too much just donates dead money.
• Dropping the small-blind limp. Playing a raise-or-fold small-blind strategy when the solve wants a limp range leaves EV on the table and unbalances the hands you do raise.
• Three-betting the big blind too wide or too narrow. The flat/three-bet split is a real decision; guessing it costs value on both sides.
• One-size-fits-all sizing. Using the same open size at 100bb and 30bb ignores how the correct size compresses as stacks shorten.
• Ignoring the structure. Applying a rake-free chart in a raked cash game, or a no-ante chart in a tournament, gets the widths wrong in opposite directions.

Cash and tournaments are not the same battle

The same seats, different math:

• In cash, rake taxes every pot that sees a flop, so blind-vs-blind play tightens and shifts toward ending the hand preflop. The cash ranges are solved on the 500z rake structure with full blind-vs-blind trees at every stack depth, so the completes and defends reflect the games you actually play.
• In tournaments, there is no postflop rake and the ante adds dead money, so blind-vs-blind ranges widen. The tournament ranges use the modern 12.5% ante and cover blind-vs-blind from deep stacks down to shove/fold.

Blind vs. blind at a glance

A quick mental map to anchor the detail above:

• The setup: two players, both already posted, nobody left to act. Dead money on offer, no reason to fear a hand behind, so both ranges are very wide.
• Small blind: a mix of raising and completing (limping), plus folds. The limp branch is real, not a leak, and it protects the hands the small blind does raise.
• Big blind: defends wide against the open, splitting between a condensed flatting range in position and a linear three-bet range with value plus blockers.
• By depth: deep (80bb and up), the full limp, raise, three-bet, and postflop game is live; medium (40bb to 60bb), three-bets near commitment and the limp range thins; short (25bb and below), it collapses toward jam, call-jam, and small raise-or-shove decisions.
• By structure: raked cash tightens everything and pushes toward three-bet-or-fold; the tournament ante widens everything.

How to study the spot

Because blind versus blind is so high-frequency, it is one of the highest-return spots to drill. Work it in layers: learn the small blind's raise-or-complete-or-fold split at your most common depth, then the big blind's flat-or-three-bet-or-fold response to it, then repeat one depth shorter. Owning the complete solved trees (raises, completes, defenses, and three-bets, at every stack depth) turns the hardest recurring spot into one you have already drilled, instead of one you improvise every orbit.