Cutoff CO Opening Range Guide: Building Efficient Blind Stealing and Value Ranges

Cutoff Position Advantages and Strategy Core

The Cutoff (CO) is to the right of the Button (BTN) and is the last non-blind position to act preflop. The CO has two main advantages: it can observe the actions of all players except the BTN, providing rich information, and its position is superior to the blinds and early positions, making it suitable for opening with a wider range. The core goal of the CO is to steal the blinds and use positional advantage to pressure opponents postflop.

Standard Opening Range (100BB Deep, No Ante)

Generally, in a full-ring (9-handed) or 6-handed table, the CO's standard opening range against an unopened pot is as follows:

• Strong hands (value 3-bet or call): AA, KK, QQ, AKs, AKo, AQs, AQo, JJ, TT. These hands usually make up the top 5%-10% of the range.
• Medium hands (raise, willing to face a 3-bet): 99-77, ATs, AJo, KQs, KJs, QJs, JTs, T9s. These account for about 10%-15% of all hands.
• Marginal hands (raise, but often fold to a 3-bet): A9s-A7s, KTs, QTs, J9s, T8s, 98s, 87s, A5s, A4s, K9s, Q9s. These are used for stealing and postflop maneuvering, about 10%-15% of all hands.
• Fold: Other hands, such as small pairs (22-66, depending on dynamics), weak suited connectors (below 76s), offsuit high cards (below ATo).

In a standard 6-handed game, the CO's opening raise frequency is typically between 25%-35%, depending on opponents' calling tendencies and blind defense strength. A typical range example:

• Raise: All pairs (22+), all suited Aces (A2s+), AJo+, KQo, KTs+, QTs+, JTs, T9s, 98s, 87s, 76s, 65s, and some suited connectors like 54s, 43s.
• Fold: Most offsuit hands weaker than AJo, and unsuited connectors below 76s.

Stack Depth Adjustments

Stack depth affects the CO's opening range:

• Short stack (30-50BB): Tighten the range, prioritize strong hands for all-in or raise-and-get-in. Reduce marginal suited connectors, increase strong pairs and Ax hands. For example, the raising range is about 20%, folding all pairs below 88 and suited Aces below A8s.
• Deep stack (150BB+): The range can be moderately expanded, adding more suited connectors and small/medium pairs to capitalize on implied odds. However, beware of potential resteals, so maintain caution against aggressive players.
• Medium stack (100BB): Use the standard range, adjust based on opponents.

Defense Against Different Positions

• Blinds (SB/BB): The blinds usually defend with a wide range (especially BB), so the CO can use more connectors and suited hands to exploit position postflop. If the blinds are tight-passive, significantly widen the range to steal.
• BTN: The BTN has positional advantage and may 3-bet with a wide range. The CO should avoid raising hands vulnerable to re-resteals (like ATo, KJo) and instead use strong suited hands like ATs, KJs that can call a 3-bet.
• Early position (EP/MP): If there are limpers from early positions, the CO can raise to isolate and extract value with the standard range.

Strategy Against 3-Bets

• 4-bet value range: QQ+, AKs, AKo (about 2.5% of hands). If the opponent's 3-bet range is wide, add JJ, AQo.
• Call 3-bet range: TT-77, AQs, AJs, ATs, KQs, KJs, QJs, JTs, T9s, and some suited connectors. Avoid calling with weak marginal hands (e.g., A9s, K9s) unless pot odds are favorable.
• Fold range: All hands not in the above ranges. Against tight-aggressive opponents, fold medium pairs and weak suited hands.

Practical Examples

Example 1: 6-handed, effective stack 100BB, folded to CO with A♠9♠. Standard strategy: raise, because A9s has sufficient frequency to flop a flush or top pair. If the BB is tight-passive, raise to 2.5BB; if BB is aggressive, consider raising larger (3BB) or folding.

Example 2: 9-handed, CO with K♣Q♦, a player limps from EP. Recommended: raise to isolate, aiming to force the limper to fold or go heads-up. Limpers are usually weak, and KQo easily makes top pair postflop.

Example 3: Deep stack 200BB, CO with 7♠6♠. If the blinds defend tightly, raise to steal; if the blinds are loose and aggressive, fold, as 76s may face a large 3-bet in deep stack play, which is disadvantageous.

Key Points for Range Dynamic Adjustment

• Based on blind player data: If the blinds fold too much, significantly increase steal frequency (use 35%+ range).
• Based on BTN 3bet frequency: If BTN 3bets often, tighten CO opening range and increase 4bet frequency.
• Consider ICM: In tournaments, when CO is near the money bubble or final table, tighten range and reduce marginal hand raises.

Summary

CO opening range needs to balance value and bluffs, adjusting flexibly based on stack sizes, opponents, and dynamics. Mastering the standard range is fundamental, but exploiting opponent weaknesses is the key to profitability. It is recommended to record different opponent reactions after CO raises in practice and continuously optimize the range.

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Note: The ranges described in this article apply to a general tight-aggressive (TAG) style. Exploitative plays need to be adjusted based on actual opponents.