A running glossary of GTO and poker strategy terms used throughout BalancedRange.
A circumstance that occurs on the flop when the combination of a player's hole cards and the community cards constitutes 3 of the 5 cards required to complete a flush or straight. Completing the draw requires cards that connect to the flush or straight to appear on both the turn and the river. Because this only happens about 4% of the time for a backdoor flush draw, it's rarely enough equity to justify a play on its own — it's usually cited as a secondary factor alongside some other reason to continue.
A card in our hand that, because we're holding it, can't also be in our opponent's hand — reducing the number of combinations of a given hand type they could still have. Blockers are often the swing factor between decisions at the margin, where we're otherwise theoretically indifferent.
One common case: facing an all-in decision on the river while holding just one pair. Our pair beats all of our opponent's bluffs but not much else. If there are three cards of one suit on the board and one of our hole cards is the Ace of that suit, we block our opponent from having the nut flush as one of their value hands. All things being equal, this fact alone may be enough to sway our decision from fold to call.
Blockers can have the opposite effect too: if we hold a card that blocks our opponent's most likely bluffing combos instead of their value combos, their bet now skews more toward genuine value in the range we can't rule out — which may be enough to sway our decision the other way, from call to fold.
A situation that arises when a player's range is very unlikely to contain the strongest possible hands for a given board — usually because they took an action along the way that a player holding one of those top hands would rarely take. The classic example is checking back a scare card, like one completing a flush or straight, instead of betting: a player with the actual nuts would almost always bet there for value, so checking signals their range no longer has much of those strong hands in it. A capped range is exactly what a float or other later-street bluff is attempting to exploit — since the top of the range has effectively been removed, a bet into it with a bluff has a much higher success rate.
Abbreviation for continuation bet: a bet made by the player who was the aggressor (the last raiser) on the previous street, when they're first to bet on the new street — “continuing” their aggression into it. It's most often discussed on the flop, where the preflop raiser bets again after everyone checks to them, but the term applies just as well to the turn or river if that same player is again the first to bet. (Betting two streets in a row like this is sometimes called a “double barrel,” three in a row a “triple barrel.”)
A closely related stat, c-bet frequency, measures how often a player follows through: the percentage of c-bet opportunities — hands where they were the prior street's aggressor and got the chance to bet first — where they actually bet instead of checking.
A bet made by the player who was not the prior round's aggressor, made before that prior aggressor has had a chance to act on the new street. The most common scenario is after the big blind calls a button raise pre-flop: acting first on the flop (since post-flop action starts from the first live player left of the button), the big blind bets out instead of checking to the button — leading into the preflop raiser rather than waiting for them to continue their own aggression.
The term carries a somewhat informal, historically dismissive connotation (from “donkey”), but modern solver-informed strategy recognizes donk-betting as a legitimate play in the right spots — particularly on boards where the caller's range is favored over the raiser's.
The maximum amount that can be wagered in a given pot. In two-player pots, the effective stack equals the smaller chip stack of the two players in the pot. If there are more than two players in a hand, a situation may arise where there are multiple effective stacks.
Take for example a hand where player A has 500, player B has 300, and player C has 200. Because the most player C can wager is 200, the effective stack for any pot involving player C is 200. If player C then goes all-in and players A and B continue contesting the pot, a side pot develops between just the two of them — its effective stack is the smaller of their two remaining stacks after both have called C's all-in. Here, A has 300 left and B has 100 left after calling, so the side pot's effective stack is 100 (B's remaining stack).
The probability our two hole cards will form the best 5-card hand at showdown. More precisely, the probability that the best 5-card hand we can make from any combination of our 2 hole cards and the 5 community cards ends up strongest by the river. Because equity is a running probability rather than a fixed value, it can be calculated — and it changes — at any point in the hand, not just once all five community cards are out. It's critical to determining the action that maximizes our EV (see below): the right play depends on how our equity compares to the price we're being asked to pay (see Pot Odds), not just on whether we currently hold the best hand.
Taking an action (typically a bet or raise) that prevents an opponent from profitably realizing equity they otherwise have. Suppose our opponent donk-bets with a draw. If we shove all-in with our over-pair, we deny them the chance to realize that equity cheaply: they can fold, giving up their draw's chance to hit without losing anything further, or call anyway at odds that don't justify chasing the draw, which is genuinely -EV. Either way we profit — if they fold, we win the pot immediately regardless of our actual hand strength; if they call, we profit from the bad price they accepted.
How much of a hand's raw equity (see Equity) actually turns into won money by the end of the hand, compared to what that raw number alone would predict. Raw equity only tells you how often a hand would win if every remaining card were simply dealt out with no more betting — but real hands involve decisions on every street, and not every hand gets the chance to see all of them through. A hand realizes 100% of its equity when it wins exactly as often as its raw number predicts; it under-realizes when practical play — having to fold, getting bluffed off, being out of position — causes it to win less than that, and over-realizes when it wins more, for example by applying enough pressure that opponents fold hands that actually had it beat.
Position is the biggest driver of equity realization: acting last gives a player more information before committing more money, letting them continue with hands that have real equity but would otherwise be too risky to play out of position. This is also why a hand's “playability” matters beyond its raw equity number alone — a suited, connected hand that can make straights, flushes, and two pair in multiple ways realizes its equity better than a hand that's only ever going to be a single pair, since it has more ways to keep playing profitably as the hand develops. It's the flip side of equity denial (see above): equity denial is what one player does to reduce an opponent's realization, while equity realization describes how well a hand converts its own raw chances into real winnings.
For example, on a King-Queen-Ten flop that's all one suit, if we have a pair of 2s and our opponent holds any two unpaired over-cards with one card matching the board's suit, they have more total equity than we do: in addition to their flush draw, almost any card they pair up — or use as a kicker if the board pairs — beats our hand too. (This specific reasoning leans on hero holding the worst possible pair; it wouldn't apply the same way against, say, pocket 9s.)
Abbreviation for Expected Value, the average outcome of a decision, calculated by weighting each possible result by its probability. In poker this is usually framed as (probability of winning × amount won) − (probability of losing × amount lost). An action (bet, check, call, fold) is +EV if it wins money on average over the long run. -EV plays can still win a given hand and +EV plays can still lose one. EV describes the average over many repetitions, not any single outcome.
A call made with a speculative hand that has limited to no direct showdown value, with the primary plan of taking the pot away on a later street if the original bettor checks. The classic scenario is calling a flop c-bet: if the aggressor checks the turn — often a sign their range has become capped, since a player with genuinely strong hands would usually keep betting — the floater can bet into that checked-to spot as a bluff, regardless of what they actually hold.
A secondary benefit of floating is that it helps meet the minimum defense frequency (see MDF): a range often doesn't contain enough genuinely strong, showdown-capable hands on its own to hit the required continuing frequency against a bet, so some weaker, speculative hands need to call as well, purely to keep the range unexploitable.
A method for choosing bet and raise sizes across multiple remaining streets using the same bet-to-pot ratio on every street, calculated so a player's entire remaining stack gets committed by a target street — typically the river — via a final bet at that same ratio.
For example, with an effective stack of 100 and a pot of 40 going to the flop (SPR = 2.5), getting all-in smoothly across the flop, turn, and river works out to roughly 40% of the pot on each of the three streets. That ratio applies uniformly to every street in the sequence, not specifically the river — and whether it lands above or below a full pot-sized bet depends entirely on the starting SPR and the number of streets remaining. Shallower stacks or more remaining streets tend to produce sub-pot-sized geometric bets, like the example above; very deep stacks with few streets left can actually require overbet-sized geometric bets to get all-in by the river — part of why overbetting became such a prominent solver-era strategy.
Short for Game-Theory Optimal. It's a way of playing where an opponent can't find any way to beat you in the long run, no matter what they try. In heads-up poker (just two players), if both players play perfect GTO, the game evens out — nobody wins or loses over time, before things like blinds or the casino's rake come into play.
One catch: that “can't be beaten” guarantee really only holds with exactly two players. Once a third player joins the table — like in 3-max or 6-max — GTO stops being a sure thing, since with more players there can be more than one “correct” way to play at once.
No-limit hold'em also hasn't actually been fully solved — there are simply too many possible bet sizes to check every one. (Fun fact: a simpler version of the game, heads-up Limit Hold'em, basically was solved back in 2015 by researchers at the University of Alberta.) Instead, poker solvers get close by simplifying the problem — grouping similar hands together and testing a smaller set of bet sizes — then playing millions of practice hands against themselves until they land on a strategy that's nearly impossible to beat, even if not mathematically perfect.
An abbreviation for Independent Chip Model. ICM's mathematical foundation is often traced to a formula originally developed for estimating probabilities in horse racing (commonly credited to statistician David Harville), later adapted to poker tournaments — most commonly credited to Mason Malmuth for bringing it into poker theory — based on the insight that in a tournament, one player will eventually end up with all the chips, but that player does not win all of the prize money.
Thus, each additional chip gained in a tournament is worth less than the chips one started with, and the very last of one's chips — the ones that keep a player alive — are the most valuable of all. ICM quantifies this insight, translating a player's chip stack into the expected prize money they can expect to win with it, given the tournament's payout structure.
In spots where prize money escalates rapidly in value, like on the money bubble, ICM produces some often counter-intuitive insights — for example, it can be correct to fold even pocket Kings pre-flop against a similarly large stack's shove, if there are other short-stacked players elsewhere in the field more likely to bust out on their own. The bigger stack has disproportionately more to lose in ICM terms than it stands to gain, so it can afford to wait rather than risk elimination unnecessarily.
In poker, the largest bet size we can get a worse hand to call. If we knew our opponent's exact hand, this would be easy to calculate — but since we can't see their cards, we instead estimate the range of hands they're likely holding based on how the hand has played out, and pick the bet size that earns the most on average across that entire range, not just the size that would work against their single strongest possible holding.
This is closely tied to bluffing: because a balanced strategy uses the same bet size for bluffs and value bets for a given decision (so opponents can't read your hand from your sizing alone), the size that folds out the weak end of an opponent's range and the size that still gets called by the strong end of the range you're targeting end up being close to the same number.
Abbreviation for Minimum Defense Frequency: the minimum percentage of the time we need to continue (call or raise, not fold) against a bet, so our opponent can't turn a guaranteed profit by betting any two cards regardless of what they're actually holding.
MDF = Pot ÷ (Pot + Bet). If the pot is $100 and the opponent bets $100 (pot-size), MDF = 100 ÷ 200 = 50% — we need to continue at least half the time. A smaller bet raises the required defend frequency: a $50 bet into that same $100 pot needs MDF = 100 ÷ 150 ≈ 67%, since the opponent is risking less to win the same pot.
Fold more than this allows — in the $100-bet example, continuing less than 50% of the time — and the opponent can profit by betting any two cards, since we're now folding often enough that even a guaranteed-worst-hand bluff shows a profit.
A hand range composed of very strong hands and very weak ones, with the middle largely missing. Polarization is mainly driven by bet size: a large bet or raise forces a split, since a medium-strength hand usually doesn't want to risk a lot of chips for a modest edge — it would rather just call or check and see a cheap showdown. That leaves big bets and raises populated mostly by hands that either want maximum value (genuine strength) or maximum fold equity (bluffs).
Dry, paired boards are a common setting where this becomes especially clear, since there's little “medium value” territory to begin with. For example, if the flop comes 4-4-2 and the big blind donk-bets, then the button raises, both players' ranges are likely polarized — there's little reason to make either move with a merely decent hand on a board this unlikely to have improved anyone, so each range skews toward real strength (trips, big pairs) or a bluff.
The opposite of a polarized range is a merged (or linear) range, which includes the full spectrum of hand strengths — typical of smaller bets or calling lines, where medium-strength hands are happy to stick around.
The ratio of the amount in the pot to the amount we must call. For instance, if the pot has $3 and it costs $2 to call, our pot odds are 3:2, or 1.5:1 — which converts to needing at least 40% equity to break even (2 ÷ (3+2) = 40%). If we're acting rationally, our probability of winning the hand must match or exceed that percentage to make calling worthwhile.
A circumstance that arises in poker when the mathematically correct play is to call even though a hand's equity has degraded. This usually occurs when a player has a short stack relative to the pot, since the already-invested money makes the price to continue very cheap. For example, suppose player A starts the hand with 14 BBs and player B with 38 BBs. Blinds and antes total 3 BBs, and each player contributes 3 BBs pre-flop and 5 BBs on the flop, making the pot 19 BBs with player A down to 6 BBs remaining. Suppose player A has 36% equity on the flop, and the turn brings A's equity down to 20%. If player B shoves, A can only ever call for their remaining 6 BBs (see Effective Stack) — so calling costs 6 to win a 31-BB pot (19 + B's matched 6 + A's own 6), requiring about 19% equity. Since A's actual equity (20%) still clears that bar, calling remains the higher-EV play despite being a heavy underdog after such a large equity collapse. Awareness of pot odds and stack sizes is what allows a player to think ahead and avoid this pitfall before it can occur, usually by playing a push/fold strategy on an earlier street.
In No Limit Hold'em, a player's range is the full set of plausible starting cards they could hold at a given point in the hand, based on the actions they've taken. Range is shaped by several factors — bet sizing, stack depth, number of players in the hand, and position — and pot odds (see above) is often the biggest factor of all: a player who's already invested chips and faces a cheap price to continue can profitably defend a much wider range than one who has to pay full price to enter the pot.
For example, if the first-position player makes a minimum raise, the big blind might call with almost any two cards — not because of some positional information edge, but because they've already posted money and only owe a small amount more, getting a great price. A player cold-calling that same raise from second position, by contrast, owes the full call amount and gets no such discount — so their range would be considerably narrower, since calling signals they believe their equity is good enough to justify the price they're actually paying.
An abbreviation for Sklansky-Chubukov number, from a table that emerged from a collaboration between poker player and mathematician David Sklansky and Alexander Chubukov. For a given hand, the table lists the maximum stack depth, in big blinds, at which shoving that hand from an unopened pot remains profitable — even in the theoretical worst case that the opponent could see the hand face-up before deciding whether to call. Because a real hand is never actually face-up, a player can usually profitably shove hands weaker than what the bare table alone would suggest, since concealment adds extra value beyond that conservative floor. What the SC number provides, then, is a theoretical minimum — a baseline for the class of hand a player should be prepared to shove first-in, understood to be exceedable in practice.
An abbreviation for stack-to-pot ratio: the ratio of a player's remaining chips (specifically, the effective stack — see above) to the size of the pot. SPR's importance cannot be overstated — it's one of the most important factors in determining a player's correct strategic choice in cash games, and remains a major consideration in tournament play as well.
An SPR below one means a player has fewer chips remaining than the current size of the pot. When players talk about being “pot committed,” they're usually describing a situation where SPR has dropped low enough that even a hand with fairly minimal showdown value is priced in well enough to continue — the price to call has simply become too good to fold, even though the hand itself isn't strong.