Information lands, SPR compresses, and barrels earn their keep.
The turn is where most players’ plans fall apart. A fourth board card arrives, stack-to-pot ratios shrink, and ‘I had a plan on the flop’ becomes a real decision with less room to manoeuvre.
Barreling (betting flop and turn) works when your range still has the nut advantage and their continue range is capped. Probe bets (betting when the aggressor checked) steal pots when they give up. Both need a reason — blockers, board change, or a polarised story.
Think in SPR: as the pot grows relative to stacks, you commit or release. The turn is often the last cheap street to get information before the river forces a binary choice.
SPR
Stack-to-pot ratio. Low SPR means commitment decisions; high SPR means room to manoeuvre.
Barrel
A second (or third) street bet after taking the lead — pressure on capped ranges.
Probe
A bet after the previous aggressor checks — often a thin value or delayed steal.
Range check
Checking a strong range on a scary turn to protect the checking range and induce.
Li walks through a turn call with a flush draw where immediate pot odds aren't enough — but river implied odds (villain paying off when you hit) justify continuing. The turn is where that implied-odds bet often gets made or broken.
Before you call the turn, name the river bet size you expect to collect. No river plan → turn call is hope, not math.
Source — Li (2018). Exploitability and GTO Play in Poker. Boletín de Matemáticas.
Exploitability and Game Theory Optimal Play in Poker
Li (2018). Exploitability and GTO Play in Poker. Boletín de Matemáticas.
Single-hand EV maximisation can lose long-run — ranges, implied odds, and balance matter across hands.
Most Important Fundamental Rule of Poker Strategy
Ganzfried & Chiswick (2020). Most Important Fundamental Rule of Poker Strategy. AAAI.
MDF alone is incomplete — integrate range advantage: defend at min(MDF, MDF − ½·RA + ¼).
You c-bet K♠ 7♦ 2♣ as BTN, BB calls. Turn is 2♥. Do you barrel light, or check?
Barrel is fine at a solid frequency — the board got drier, BB’s floats are still mostly air and weak pairs, and the pair of deuces rarely improves their range more than yours. Mix in some checks with medium strength so your check-back range isn’t pure air.
On the turn, ask: did the board help their continue range, and is SPR still friendly? Then barrel, probe, or give up on purpose.