Cutoff CO Preflop Range and Strategy Explained

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analysis of cutoff CO preflop range and strategy in 6-max cash games. Covers standard open-raising range, defense and attack against raises from different positions, adjustment factors such as stack depth and opponent tendencies, as well as GTO reference and practical application, helping you make optimal decisions in the CO position.

Position Overview

The Cutoff (CO) is positioned before the Button (BTN) and is the third-latest position in a six-handed game. The CO has an information advantage over early positions (can observe earlier actions) but is not as good as the BTN (cannot close the preflop action). The core of CO's preflop strategy is to use positional advantage to widen the entering range while considering the squeeze risk from later players.

Recommended Range

The following is the standard CO open-raise range for six-handed 100bb effective stacks (assuming opponents are not adjusting):

Range Construction Logic

The CO range is based on the following principles:

  1. Position advantage compensation: Compared to early positions, the CO has better information, allowing a wider entry standard. However, compared to the BTN, the CO is at a positional disadvantage against squeezes from later players (especially 3bets from BTN and blinds), so overly wide raising is not suitable.
  2. Playability priority: Suited hands, connectors, and pairs that easily form draws or made hands postflop have higher priority. A-high hands are strong but easily dominated, so they should be slightly widened in late position.
  3. Avoid deep-rooted mistakes: Avoid entering with offsuit hands like A9o, K8o that are easily dominated, as these hands are very difficult to play postflop.

Adjustment Factors

Adjust the range based on the following situations:

  1. Stack depth (effective stacks)
    • Deep stacks (>150bb): Increase proportion of suited connectors and small pairs (e.g., 65s, 44) for better postflop big pot battles; reduce offsuit A-highs.
    • Short stacks (<40bb): Tighten open range, prefer strong hands to push (e.g., TT+, AQ+); reduce semi-bluff 3bets.
  2. Opponent tendencies
    • Late position players (BTN, blinds) frequently 3bet: Tighten CO range, reduce weak hands entering, and punish with strong 4bets.
    • Blinds are tight-passive: Can widen open range, use position to steal blinds.
  3. Raise sizing
    • Standard CO open is usually 2.5-3bb. If blind defense is weak, reduce to 2-2.2bb; if late position aggression is high, raise to 3-3.5bb to reduce odds for weak calls.

GTO Reference

According to poker GTO solver theory, at 400bb effective stacks, the CO preflop optimal open range is about 20-22% of hands, including all pairs (22+) ~6%, suited connectors and gapped suited (e.g., T9s, J8s) ~12%, and some offsuit A-high and K-high ~4%. The 3bet frequency is about 6-8%, with a value-to-bluff ratio of about 1:1.5. However, in actual gameplay, players should not pursue perfect GTO but instead use exploitative adjustments against opponents.

Practical Application

  • Against tight-passive blinds: Increase steal frequency, use hands like A5o, K7s to raise to 2.2bb, and profit from continuation bets postflop.
  • Against aggressive 3bet BTN: Tighten entering range, only raise with AQ+, 99+, and frequently 4bet or call defensively (e.g., call 3bet with TT, AQ, then continue if hit strong hand postflop).
  • Facing an early position raise: When in CO facing an UTG raise, 3bet with TT+, AQ+, flat call with some suited connectors, and plan to semi-bluff aggressively when hitting draws postflop.
  • Multiway pots: If multiple players limp in, the CO can call with suited connectors and medium pairs, but avoid participating with weak offsuit A-highs that are easily pushed out.