Blind vs Blind Poker Strategy: SB vs BB (BvB) Guide
Last updated: May 19, 2026
Blind vs blind (BvB) is the most frequent postflop matchup between two specific positions in Texas Hold'em — every hand that folds to the small blind creates a heads-up BvB situation. It is also the most strategically unique: both players were already forced to invest money preflop, neither player has the BTN (the small blind is always out of position postflop), and the ranges are the widest of any two-player matchup.
The small blind should open 45–55% of hands: wide enough to exploit the half-price discount but tight enough to avoid postflop disasters out of position. The big blind defends aggressively: a 3-bet frequency of 10–15% keeps the SB from profiting with any two cards.
Preflop — SB Opening and BB Defense Ranges
BvB is the only heads-up preflop matchup where both players operate with unusually wide ranges. The SB opens wide to recoup the forced investment; the BB defends wide because pot odds make most hands profitable calls.
BvB preflop action frequencies
SB standard open sizing is 2.5bb — identical to a BTN open in absolute terms. Some players use 3bb from SB to reduce BB calling frequency, accepting a slightly smaller pot to play more often in position (the BB being the caller). Both sizings are solver-approved depending on the pool tendency.
Why SB Opens So Wide
The core math: the SB has already paid 0.5bb into the pot. When facing a fold-or-open decision, the SB is essentially getting a 2:1 discount on every open. Opening vs folding: you only need approximately 30% equity to profit when you're already getting 2:1 on the half-bb already invested.
SB holds a paradox: price advantage before the flop, worst position after the flop. The balance is to exploit the discount preflop with wide opens, then compensate postflop with disciplined OOP play — lower c-bet frequencies, more check-calls, fewer bluffs on later streets. A SB that opens 55% and plays correctly OOP will run above 0 EV in this spot despite the positional disadvantage.
The half-bb discount breakdown
BB Defense Ranges — The 60–70% Rule
BB defends wide because of pot odds. Vs a 2.5bb open, BB pays 1.5bb to win 4bb (the SB's 2.5bb plus BB's own 1bb already in the pot) — that is 2.67:1 pot odds. BB needs only 27% equity to profitably call. Most hands in the BB clear this threshold; only the genuine trash (72o, 83o, 94o) falls below it.
The 3-bet range from BB should be structured as a polarized linear range:
Value 3-bets (QQ+, AKs, AKo)
Hands that want to bloat the pot and potentially get all-in preflop. 3-betting QQ protects it from a SB's wide range seeing a cheap flop with hands like KJo or A7s.
Bluff 3-bets (A5s–A2s, suited connectors)
Ace-low suited hands block SB's strongest holdings (AA, AK) while having playable equity on many board textures. Suited connectors (65s, 76s) provide nut-flush and straight draws.
Call range (remaining 60–70%)
Hands with enough equity to call 2.5bb but insufficient range advantage to 3-bet. Includes hands like K9o, T8s, 44, Q6s. These hands play IP postflop and benefit from the positional advantage.
Postflop Dynamics — SB is OOP, BB Has Position
The BB holds a significant positional advantage postflop. Acting last on every street allows the BB to see how the SB reacts to the board before committing chips — a fundamental information edge. BvB postflop tendencies diverge sharply from BTN vs BB play:
The SB c-bet frequency of 40–50% is notably lower than the BTN's typical 55–65%. Without positional advantage, the SB cannot as easily barrel off opponents or represent strong hands credibly across all board textures. SB should prefer small c-bets (25–33% pot) when betting, to keep the pot manageable OOP.
Donk Betting in BvB — A Unique Line
In BvB, donk betting (BB leads into SB after check-calling preflop) is more common and profitable than in other matchups. On 7-5-2 boards or 9-8-4 connected boards, the BB's wide calling range hits these textures significantly harder than the SB's more structured opening range.
BB donk-betting 30–40% pot is a GTO-supported move in BvB specifically. The logic: when the BB calls a 2.5bb open with hands like 76s, 85s, 54s — these hands connect much more often with low, connected flop textures than the SB's range that skews toward broadway hands (AT+, KQ, KJ). By donk-betting these boards, the BB denies SB's ability to realize equity cheaply with overcards and forces a decision with range advantage.
Board textures where BB donk-bets most
Common BvB Mistakes
SB playing too tight preflop (folding >55%)
The half-bb discount makes this a costly error. Every fold from SB throws away 0.5bb of already-invested equity. SB should exploit the price, not yield the spot.
BB over-calling 3-bets from SB
Many hands that justify a preflop call don't have the equity to call 3-bets from the SB. When SB 3-bets back, BB's calling range should tighten to hands with genuine value (TT+, AQs+) or strong blockers.
SB c-betting too frequently OOP (>60%)
Without the BTN's positional advantage, c-bets lose EV faster against the BB's wide defending range. Over-betting forces money into spots where the SB cannot realize equity efficiently.
BB never donk-betting
Leaving the donk bet line completely unexploited hands the SB free c-bets. On low, connected boards, BB's range advantage is real — don't donate that edge by always checking.
Both players ignoring range width
In BvB, standard hand-reading heuristics break down. Strong top pair, weak kicker (e.g. K4o) is a realistic holding for either player. Avoid over-folding or over-bluffing based on assumptions from other positions.
Definitions
Frequently Asked Questions
What is blind vs blind (BvB) in poker?
Blind vs blind (BvB) refers to the preflop and postflop matchup between the small blind (SB) and big blind (BB) when all other players fold. It occurs every time the action folds to the SB, creating a heads-up pot between the two players who posted forced bets. BvB spots are characterized by wide ranges, OOP play for the SB, and frequent postflop action.
How wide should the small blind open in BvB?
The small blind should open approximately 45–55% of hands in BvB situations. The half-price investment (0.5bb already in) justifies a wide opening range. Standard sizing is 2.5bb (or 3bb if you want to reduce BB calling frequency). Tighter SB openings (below 40%) leave significant EV on the table by forfeiting the blind investment too often.
How should the big blind defend vs small blind opens?
Call approximately 60–70% of hands and 3-bet 10–15% of the time. Fold only the bottom 20–30% of your range — hands with zero playability like 72o, 83o. The wide defense frequency is justified by pot odds: vs a 2.5bb open, the BB pays 1.5bb to win 4bb (2.67:1), meaning any hand with >27% equity is a call.
Who has position in blind vs blind?
The big blind has position postflop — the BB always acts last after the flop, turn, and river. This is a significant advantage. The small blind is first to act OOP in all postflop streets. This positional dynamic explains why BB has a higher 3-bet frequency, more check-raises, and donk bet opportunities than the SB.
What is donk betting in BvB?
A donk bet in BvB is when the big blind leads out into the small blind on the flop (the OOP player bets first, into the preflop aggressor). In standard BTN vs BB situations, donk betting is unusual. In BvB, it is GTO-supported on boards that connect heavily with the BB's wide calling range (low connected boards, paired boards). Standard donk sizing: 30–40% pot.
Why is BvB more complex than other positional matchups?
BvB complexity arises from four factors: (1) Both ranges are extremely wide (SB opens 50%, BB defends 70%), making hand-reading difficult; (2) Neither player has the classic 'button advantage' — SB is OOP but has initiative, BB is IP but is the caller; (3) Donk bets, check-raises, and probes are all high-frequency; (4) Both players frequently have weak-to-medium holdings, making river showdowns swingy and high variance.
Related Guides
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