4-betting and facing 4-bets

Most players treat the 4-bet as a courage decision — "do I dare?" The winners treat it as a combinatorics decision. When you face a 3-bet, your hand barely matters; what matters is which of villain's combos your cards remove.

Walk through the math. Against a competent 3-bettor, the hands that *call or 5-bet* a 4-bet are roughly QQ+ and AK. Count the combos:

• AA: 6, KK: 6, QQ: 6 → 18 pair combos
• AK: 16 combos

Holding an ace knocks AA from 6 combos to 3, and AK from 16 to 12. Holding a king does the same to KK and AK. That's why the canonical 4-bet bluffs are the ace-x suited wheel cards — A5s, A4s, A3s, A2s — and secondarily KQs/AQs when you have other reasons.

• A5s removes top-of-range combos *and* keeps a backup: when it gets called you flop a nut-flush draw or wheel equity.
• 72o removes nothing and flops nothing — it is never a 4-bet bluff, no matter how "balanced" you want to feel.

The leak this fixes: 4-betting random air (or worse, only ever 4-betting KK+ so you're face-up). Pick bluffs by *removal*, not by feeling brave.

4-bet sizing is depth-dependent, and the single most common sizing leak is 4-betting too big, which pot-commits you against the exact hands you wanted to fold out.

Anchor everything to the 3-bet size. Say it's 100bb deep, you open 2.3bb, button 3-bets to 8bb.

• In position (you're the 3-bettor's target, acting last): 4-bet to ~2.2x the 3-bet → ~18bb. Position lets you size down.
• Out of position (you opened from EP, blinds 3-bet): ~2.5x → ~21bb. Bigger to deny the caller's price and positional edge.
• vs an out-of-position 3-bet (they 3-bet from the blinds into your open): you can use a small "snap" 4-bet to ~16–17bb. They're capped and OOP; a small 4-bet keeps your bluffs cheap and still folds out their air.

The geometry that matters: at 100bb a ~21bb 4-bet leaves ~79bb behind — you are not committed, so you can still fold to a 5-bet jam. The moment your 4-bet crosses ~25% of the effective stack you've lost that option. Keep one size for value and bluffs on each line; sizing up with bluffs is a tell the trainer's bots and any reg will tax.

Your 4-bet range is polarized: nutted value plus blocker bluffs, nothing in between. The ratio isn't a vibe — it's set by the price you lay your opponent.

When you 4-bet to 21bb into a 9bb pot and they must call/jam, you're risking enough that you need roughly a 2 value : 1 bluff mix at 100bb to stay unexploitable. Practically:

• Value (100bb): KK+, AK, and AKs/QQ mixed vs aggressive 3-bettors. AA/KK are pure 4-bets — slow-playing them invites a flat that lets villain realize equity.
• Bluffs (100bb): A5s–A2s first; A4o/A5o and KQs as you need volume vs a wide 3-bettor.

Now change the depth — this is where most players go wrong:

• Shallower (40–60bb): the 4-bet becomes nearly committing, so the bluff portion shrinks and your value range widens to include AK/QQ as pure 4-bet-jams. You're not folding to a 5-bet anyway, so bluffs lose their escape hatch.
• Deeper (150bb+): you can add a *few* more bluffs and even consider 4-betting AQs/KQs lighter, because the implied odds of stacking them postflop when called are higher — but expand cautiously OOP.

Rule of thumb: the deeper you are, the more your 4-bet can be a bluff; the shorter you are, the more it must be the nuts.

A balanced 4-bet range is your *default*. The money is in deviating against the specific 3-bettor — and the trainer flags both over- and under-4-betting.

• vs a 3-bet-happy button/blind (3-bets >12–14%): their range is full of A5s-type air. Crank up bluffs and even 4-bet KQs/ATs thin — they fold the bottom of their range and you print. This is where most of your 4-bet *volume* should live.
• vs a tight EP/UTG 3-bettor (only `QQ+`/`AK`): 4-bet bluffs near zero. You're bluffing into a range that never folds and crushes you. 4-bet only KK+ for value here, and even consider just *flatting* AK to keep their bluffs in.
• vs a player who folds to 4-bets too often (folds >55%): 4-bet any two with a relevant blocker as a pure steal — A2o, K6s — and shrink your value 4-bets (just flat QQ/AK to trap, since they won't pay the 4-bet).
• vs a 5-bet-jam maniac: widen value, drop bluffs. Let them stack off into KK+/AK.

The meta-leak: a static 4-bet range. If you only ever 4-bet KK+, observant villains fold every 3-bet to your 4-bet and you never get value — and they 3-bet you relentlessly knowing your opens are capped.

You 3-bet, you get 4-bet, and now the leak surfaces — players either fold their whole range (printing for the 4-bettor) or hero-call/jam too wide. Build three buckets at 100bb:

• 5-bet jam (value): KK+, and AK versus aggressive or unknown 4-bettors. AA always jams or traps; never fold it. QQ/AKs jam vs players you read as 4-bet-bluffing.
• Call the 4-bet: thin and rare at 100bb because you're often capped and OOP. The best flats are QQ/JJ and AKs *in position* with room to play a flop — and only when stacks are deep enough that a ~21bb call leaves real postflop maneuverability.
• Fold: the entire bottom of your 3-bet range — A5s, KQs, T9s, 87s and the rest of your bluffs. They did their job folding out air; dumping them to a 4-bet is correct, not weak.

The critical insight: your A5s 3-bet bluff is *supposed* to fold to a 4-bet. The mistake is the reverse — calling A5s or KQo "because I already invested," then check-folding the flop. Sunk cost is not equity.

Quick MDF sanity check: a 21bb 4-bet into a pot of ~12bb lays you a price where you'd need to continue ~36% of your range to be unexploitable — but unexploitable defense is irrelevant against a tight 4-bettor who's never bluffing. Against the nit, over-fold. Against the maniac, defend toward MDF by widening your 5-bet jams, not your flats.

Everything above is chip-EV. In a tournament, the 4-bet/5-bet game is where ICM does the most damage to careless players, because these pots routinely go all-in for stacks.

• Near a pay jump or on the bubble, kill your 4-bet bluffs first. A 4-bet bluff that's break-even in chips is a *losing* play in $EV when busting drops you a pay tier. With a pay ladder above you, A5s becomes a fold-or-flat, not a 4-bet.
• Tighten 5-bet call-offs hard. A chipEV-neutral AK 5-bet-jam can be a clear fold under ICM when a covering stack jams over your 4-bet and busting costs real equity. The classic error is stacking off QQ/AK on the bubble for 100bb because "it's a standard cooler" — under ICM it often isn't.
• Attack the covered, not the coverer. As the *big* stack, you can 4-bet bluff *more* against medium stacks who can't risk busting — they over-fold because their tournament life is on the line. ICM pressure is a weapon when you hold it and a tax when you don't.
• Short and 3-bet (15–25bb): the "4-bet" disappears into a 4-bet jam — there's no room for a non-all-in 4-bet. Jam your value (TT+/AQ+ depending on the 3-bettor) and fold the rest; a small 4-bet here just commits you with no fold equity.

Rule of thumb: chip-EV builds the range, ICM shrinks it. The closer the money, the more your 4-bets and 5-bet call-offs collapse toward only the nuts.