Heads-up strategy fundamentals

How heads-up differs from full-ring or 6-max

In a full-ring (9-handed) game, the button is one of nine positions and the typical pot has 2-4 players post-flop. In a heads-up game, every hand is button vs big blind. The button has positional advantage on every post-flop street; the big blind is permanently out of position.

The structural consequences:

1. Pre-flop ranges expand dramatically. Button opens 80-100% of hands. Big blind defends 60-80% of hands. Most pots reach the flop with both players holding a wide range.

2. Post-flop play is range-vs-range. Most flop decisions are not "do I have a strong hand?" but rather "how does my range compare to opponent's range on this board?". Both ranges are wide; range-and-board analysis becomes the primary decision input.

3. Aggression frequency is higher. Heads-up demands more c-bets, more 3-bets, more aggressive turn and river play. Passive heads-up play loses to aggressive opponents.

4. Variance per hand is higher. Wider ranges mean more marginal-equity spots and more variance-driven outcomes.

Button pre-flop ranges

The button in heads-up opens 80-100% of hands. The exact range depends on stack depth and opponent tendencies:

At 100 BB deep:

• Open ~80-90% of hands.
• Fold only the worst trash (2-3o, 2-4o, 2-5o, 3-4o, similar).
• Open everything else with a min-raise or 2-2.2× sizing.

At 50 BB:

• Open ~85-95% of hands.
• Slightly wider than 100 BB because realized equity OOP for big blind decreases at lower stack depths.

At 20 BB:

• Open ~90-100% of hands.
• Many opens become min-raise + fold to 3-bet shoves. Push-fold ranges enter for the smallest stacks.

The button's pre-flop advantage is so strong that almost every hand has positive expected value as an open. The exceptions are the worst hands that have no equity realization potential against a strong defending range.

Big blind defense

The big blind defends a wide range against the button's opens. The defending range is split between:

Calling: wide range of hands that benefit from post-flop play.

• Suited connectors and gappers.
• Suited broadway hands.
• Smaller pocket pairs.
• A-X hands that don't qualify for 3-bet (smaller A-X offsuit, A-X suited that prefers to call than 3-bet).

3-betting: polarized range — strong value + bluffs.

• Value: TT+, A-K, A-Q.
• Bluffs: A-2s through A-5s (block opponent's premium A-X), small suited connectors (some frequency), hands that play well post-flop in 3-bet pots.

Folding: the worst portion of the defending range.

• Trash hands that can't realize equity OOP.

A reasonable BB defense range vs button min-raise: 60-75% of hands defended (call or 3-bet), 25-40% folded. Wider than this against passive openers; tighter against aggressive openers.

Post-flop range thinking

In heads-up post-flop play, both players' ranges are wide. The flop, turn, and river decisions are primarily range-vs-range.

On the flop: The button has a slight range advantage on most boards because the button's opening range includes more premium hands proportionally. C-betting at a moderate frequency (40-60%) captures this range advantage.

The big blind's calling range includes more marginal hands that miss the flop frequently. The c-bet captures these "miss" hands and forces folds.

On the turn: Range narrowing accelerates. Hands that called the flop with marginal equity often miss the turn and fold to a continued bet. Strong turn play involves recognizing which boards favor continued aggression (when the turn helps the c-bettor's range) and which boards favor checking back (when the turn helps the caller's range).

On the river: Polarization peaks. The river decision is typically "do I have a strong made hand, a marginal hand, or a missed draw?" — and the corresponding bet/check decision is based on range-vs-range thinking + opponent profiling.

C-bet frequency in heads-up

In full-ring or 6-max games, the optimal c-bet frequency is around 65-75% on most flops. In heads-up, the c-bet frequency typically drops to 40-60% because:

• The big blind's defense range is wider, so c-betting at high frequency leaves you exploited.
• The big blind's calling range includes more marginal hands that can continue to the turn.
• The button's range, while still strong, is not overwhelming enough to support 75% c-bet frequency.

The c-bet selection in heads-up favors:

• Hands with showdown value (top pair, over-pairs, pocket pairs).
• Bluffs with backdoor equity (suited connectors that picked up a flush draw, gutshots that picked up a backdoor flush draw).
• Selective bluffs with blocker logic.

Random c-betting at 75% frequency in heads-up is highly exploitable by an aggressive defender.

Aggression frequency

Heads-up demands the highest aggression frequency of any poker format. The "aggression factor" (bets + raises / calls) for a strong heads-up player is typically:

• Flop: 1.5-2.5
• Turn: 1.5-2.5
• River: 1.0-1.5

Compared to 6-max numbers (typically 1.0-1.5 across streets), heads-up players bet and raise more often. Passive heads-up play is structurally losing because the button's positional advantage demands aggression to capitalize on.

Common heads-up adjustments

Against passive opponents: Aggression frequency should increase. Passive opponents fold more than optimal; over-betting and over-bluffing captures EV.

Against aggressive opponents: Aggression frequency stays high; calling and bluff-catching frequencies increase. Aggressive opponents over-bluff; calling more often with marginal hands captures EV.

Against tight opponents: Open frequency from the button increases (steal more blinds); 3-bet bluff frequency from the big blind increases (capture more pre-flop pots).

Against loose opponents: Open frequency stays the same; 3-bet frequency may decrease (calling becomes more profitable than 3-betting when opponent's calling range is wide); post-flop value-betting frequency increases.

Stack-depth considerations

At 100 BB deep:

• Standard heads-up play. Wide ranges, aggressive flop and turn play, polarized rivers.

At 50 BB:

• Slightly tighter opening ranges (some hands lose enough equity realization to become unprofitable opens).
• More polarized 3-bet ranges.
• More commitment to flop and turn aggression.

At 25 BB:

• Push-fold enters significantly. Open ranges narrow somewhat; 3-bet ranges become primarily shoves and folds.
• Post-flop play is limited; SPR is low after any pre-flop action.

At 15 BB and below:

• Pure push-fold strategy. Almost no post-flop play.

Heads-up SNG vs heads-up cash vs heads-up hyper-turbos

Heads-up has several distinct formats:

Heads-up cash games: Stack depth typically 100 BB. Strategy is as described above. Long sessions with constant stack depth.

Heads-up SNG (sit-and-go): Tournament format with escalating blinds. Stack depth decreases over the course of the SNG. Strategy adapts from deep play to push-fold as blinds increase.

Heads-up hyper-turbos: Very fast blind structure. Typically start at 25 BB stacks and reach push-fold within 5-10 hands. Push-fold strategy dominates almost from the start.

Different formats demand different study emphases. Heads-up cash players invest heavily in deep-stacked post-flop study. Heads-up hyper-turbo players invest heavily in push-fold ranges and ICM-aware calling strategy.

Practical framework

For learning heads-up poker:

1. Study button opening ranges and big blind defense ranges first. Pre-flop strategy is the foundation; the rest of the game builds on top of correct pre-flop play.

2. Practice c-bet selection on different board textures. Build pattern recognition for which boards favor continued aggression and which favor checking back.

3. Develop opponent profiling fluency. Heads-up demands faster opponent adaptation than full-ring play because you face the same opponent constantly.

4. Maintain aggression discipline. Passive heads-up play loses. Aggression frequency must stay high even when running cold.

5. Re-study quarterly. Heads-up strategy evolves; solver outputs refine over time. Stay current with the GTO meta.

Heads-up is the most studied format in solver work and the most consistent format for practicing range thinking. Players who develop heads-up skills find their full-ring and 6-max play improves because the range-vs-range fluency transfers directly to higher-table-count formats.