Cutoff Opening Range Explanation: CO Raise Strategy and Construction Logic

Position Scenario Description

The Cut-Off (CO) is the position to the right of the dealer button. It is a favorable position at the table—postflop action usually takes place after the button, but the CO acts earlier in the preflop round. In six-handed or nine-handed tables, the CO is an aggressive position: since only the button, small blind, and big blind act after it, the CO can leverage positional advantage to open-raise with a wider range while avoiding frequent re-raises from the button.

Recommended Range (Typical 6-Max, Effective 100BB)

The following range is based on [GTO] theory and balanced strategy, suitable against most regular players. Actual ranges should be adjusted according to opponents.

• Strong Hands (Value Raise): All pairs ([22]+), all Ax hands ([A2s]+, [A9o]+, including AK, AQ, AJ, AT, etc.), [KQs], [KJs], [KTs], [QJs], [JTs], [T9s], [98s], [87s], [76s].
• Medium-Strength Hands (Mixed Raise): Some suited connectors ([65s]+), suited gappers ([K9s], [Q9s], [J9s], [T8s], etc.), unsuited high cards ([KQo], [KJo], [QJo]).
• Weak Hands (Partial Raise): Small suited connectors ([54s], [43s]), unsuited small Ax ([A2o]-[A5o]), some unsuited connectors ([JTo], [T9o]).
• Recommended Raise Frequency: ~25%-30% of hands.

Range Construction Logic

The core of constructing the CO range is to exploit positional advantage while avoiding excessive 3-bets from the button or blinds. The main logic is as follows:

1. Value Hands: All pairs ([22]-55 are medium value in small pairs, easy to flop sets; [66]+ can combat blind ranges) and strong Ax ([A9o]+) have sufficient equity.
2. Suited Hands: Suited connectors (78s+) and suited Ax ([A2s]-[A5s]) are easy to form flush or straight draws postflop and offer playability.
3. Mixed Strategy: Some medium hands like [KQo], [AJo], etc., are raised with a mixed frequency to balance the range, preventing being forced to fold too often when facing frequent 3-bets.
4. Folding: The worst hands like [J7o], [Q4o], etc., have no positional advantage and are easily dominated, so fold directly.

Adjustment Factors

• Opponent Type: If the button is tight-passive, widen the range (30%); if the button is aggressive and often 3-bets, tighten (22%) and increase [4-bet] frequency.
• Stack Depth: <40BB (short stack), reduce raises of small-medium suited connectors and increase all-in range with strong hands; >200BB (deep stack), add more speculative hands (e.g., small pairs, suited connectors) to exploit implied odds.
• Blind Style: If the small blind or big blind frequently [3-bets], tighten the range and increase value hands; if blinds fold often, widen to ~35%.
• Table Size: In 9-max, if [UTG] and MP have high fold rates, the CO can widen slightly; default range in 6-max is wider than in 9-max.

[GTO] Reference

According to common results from modern GTO solvers (e.g., [PioSOLVER]), in a 6-max game with 100BB effective stacks, no ante, and blinds 1BB/2BB, the CO open-raise frequency is typically between 22%-28%. Among them:

• Pairs: 100% [raise] (22-[AA])
• Ax suited: [A2s]-[A5s] ~75% [raise], [A6s]-[A9s] ~90%, [ATs]+ fully raised
• Ax offsuit: [A9o]+ ~60%, [A5o]-[A8o] ~30%, [A2o]-[A4o] ~10%
• Kx suited: [K9s]+ ~90%, [K8s]- ~40%
• Suited connectors: [T9s]+ fully raised, [87s]-[65s] ~70%
• Suited gappers: e.g., [J9s], [T8s] ~60%
• Other medium hands: e.g., [QJo], KQo ~70% Note: GTO is only a reference; actual play should adjust based on opponent deviations.

Practical Application

• Against Tight-Passive Players: Widen the range to steal blinds profitably. For example, against blinds who fold often, raise with hands like [A2o], [K9o].
• Against Aggressive 3-Bettors: Tighten the range, raise only strong hands, and plan to [4-bet] or call 3-bets. For example, if the button frequently 3-bets, fold marginal hands like [AJo], KQo.
• Multiway Pot: If there are multiple limpers ahead, narrow the raising range to only value hands to avoid complex pots.
• Postflop Play Hints: The CO has positional advantage postflop, so use frequent continuation bets ([c-bet]), but be cautious on wet boards.
• Example: In a 6-max game, effective stacks 100BB, all fold to you in the CO. You hold [ATo]. According to the standard range, [ATo] is a value raise hand, so raise to 2.5BB. If the button calls, flop is K72 rainbow. As the preflop raiser, you can bet about 1/3 pot as a semi-bluff, since your range contains high cards like A and K.

After mastering the CO range, you also need to combine an understanding of the 3-bet range of the button and the blinds to make optimal decisions.