PREFLOP CHART · ~9% of hands · polarized
BB 3-bet range vs CO open — 100bb cash
Against a CO open at 100bb, the big blind 3-bets about 9% of hands — meaningfully tighter than the ~14% used vs a BTN open. The reason is simple: CO opens a tighter range than BTN (~28% vs ~48%), so the equity threshold for both value 3-betting and profitably bluff-3-betting moves up. Many hands that are clear bluff-3-bets vs BTN (e.g. K7s, 65s) become flats or folds vs CO.
Range — the hands you play
- Value: JJ+, AQs+, AKo
- Bluff: A5s, A4s, K9s (mixed), 65s (mixed)
Key insights
- Drop the lower suited wheel aces (A3s, A2s) and most suited connectors from the bluff portion — CO's range has more Ax-blockers than BTN's, reducing their value as bluff combos.
- Sizing stays at ~3.5x CO open.
Frequently asked
Should I 3-bet TT vs CO open?
Mostly yes (3-bet ~70%, flat ~30% in mixed solutions). TT has enough equity vs CO's calling range to value-3-bet, but flatting realizes well too — both are close in EV.
Why fold suited wheel aces vs CO when they're 3-bet bluffs vs BTN?
CO opens a tighter, more Ax-heavy range than BTN. That means A5s and A4s lose two pieces of their bluff value: (1) the ace blocker is less unique because CO already has more Ax than BTN, and (2) when called, CO's range is more concentrated in AK/AQ which dominate wheel aces' postflop equity. The combos are still playable as flats but don't make profitable 3-bet bluffs against this opener.
How does BB's 3-bet vs CO change in 9-max games?
Slightly tighter overall. In 9-max CO opens an even tighter range (~24% vs 28% in 6-max) because there are more players left to act. BB's 3-bet drops to ~7-8%. The value portion (JJ+, AQs+, AKo) stays; the bluff portion shrinks to just A5s and a small slice of 65s/76s.