Guide to Constructing Calling Ranges Against River Raises

Positional Scenario Explanation

Assume a 6-handed table with effective stacks of 100BB. We take the example of Button vs Big Blind (the most common scenario); other positions can be extrapolated.

Scenario: Preflop, button opens to 3BB, big blind calls. Flop, turn, and river follow a standard betting line. We bet about 75% of the pot on the river, then the opponent raises to about 3x our bet (e.g., pot is 100BB, we bet 75BB, opponent raises to 225BB). Should we call?

Recommended Range

Facing a river raise, our calling range should include:

• Nut hands: e.g., top set, straight flush, full house, etc. These usually have sufficient equity.
• Medium-strength made hands: e.g., top pair top kicker (TPTK), overpair (but with caution), two pair, etc., depending on board texture and opponent tendencies.
• Some bluff catchers: e.g., top pair with weak kicker, small to medium pairs (on dry boards), A-high (when opponent's range has a high bluff frequency).

Hands not recommended for calling: pure air, low pairs (unless blockers exist and opponent bluffs too much), vulnerable made hands (easily outdrawn).

Range Construction Logic

The core of constructing a calling range is the Minimum Defense Frequency (MDF) principle. Based on pot odds, we need to defend a certain percentage of our range to avoid being exploited by bluffs.

• Calculate pot odds: The cost of calling after opponent's raise divided by total pot. For example, after we bet 75BB into a 100BB pot, the pot is 175BB. Opponent raises to 225BB. We need to call 150BB. Total pot becomes 175+225=400BB. Pot odds = 150/400 = 37.5%. So we need to call (or raise) at least 37.5% of the time.
• Our betting range should be divided into value and bluffs. Facing a raise, we fold our weakest bluffs, call or re-raise with strong value hands, and decide on medium-strength hands based on blockers and board texture.
• In theory, the calling range should consist of all hands that can beat the weaker part of the opponent's value raising range, while also including hands that block the opponent's value hands.

Adjustment Factors

• Opponent type: Against tight-passive opponents (rarely bluff), tighten your calling range, only calling with strong hands. Against loose-aggressive opponents (frequent bluffs), widen your calling range, adding more medium-strength hands and bluff catchers.
• Board texture: On wet boards (possible straights or flushes), the opponent's value raising range is narrower (only very strong hands), so we should call tighter. On dry boards, opponents may raise with medium-strength hands like top pair, allowing us to call more loosely.
• Stack depth: Deep stacked, opponents might raise with very weak hands to intimidate, so we can call more. Shallow stacked, tighten your calling range because the opponent is more likely to have a value raise.
• History: If the opponent has previously bluffed with a river raise, adjust your calling tendencies.

GTO Reference

GTO solvers (e.g., PioSOLVER) show that on low-card boards (e.g., no flush or straight draws), the calling range against a river raise is about 35-45% of our betting range. On high-card boards, the calling range can reach 45-55%.

Typical GTO calling range examples:

• Top set+: 100% call or re-raise.
• Top pair top kicker: 60-80% call (depending on kicker size).
• Overpair: 40-60% call (be wary of opponent having a set).
• Two pair: 30-50% call (higher two pair easier to call).
• Bottom pair: 10-20% call (only when blockers are strong).

Practical Application

Example scenario: Flop K♠9♦3♥, turn 7♠, river 2♣. Button holds K♣Q♦. Preflop raise, flop bet, turn bet, river bet 75% pot. Big blind raises 3x.

• If big blind is a Tag (tight-aggressive), their raising range likely includes K9+, set, or a turn straight (e.g., T8). Fold.
• If big blind is a LAG (loose-aggressive), they may raise with Kx, 9x, or even A-high as a bluff. Call.
• Blockers: If we hold A♦, reducing opponent's flush possibilities, we can call more.

Summary: Facing a river raise, don't blindly call or fold. Calculate MDF based on opponent type and board texture, and adjust your range accordingly.