Gambling terms, explained straight

Poker

GTO preflop ranges

Game-theory-optimal preflop ranges tell a player which starting hands to raise, call, or fold before the flop, balanced so no opponent can profit by exploiting them.

Also called
GTO preflop charts, opening ranges
Applies to
Preflop play in no-limit hold'em and heads-up no-limit hold'em
Key numbers
UTG folds ~90% of hands, button folds ~50%; open-raise size is usually 3 BB; 1,326 hand combos, 169 unique types 15

Key points

  • Early positions play tighter, later positions wider; the strategy is generally raise-or-fold rather than limp, except at small blind 1.
  • GTO preflop ranges are equilibrium-based and balanced, unlike broader poker preflop ranges which may be heuristic or descriptive 46.
  • They can be shown in 9-max or other formats, but the underlying concept is the solver-derived strategy, not the chart layout 23.

Where this term is used

Not the same as

Sources

  1. Are ChatGPT and GPT-4 Good Poker Players? - A Pre-Flop ... arxiv.org Provides the key numbers for fold percentages and the raise-or-fold strategy.
  2. GTO Wizard Benchmark arxiv.org Supports the term 'GTO preflop charts/ranges' and the 9-max format distinction.
  3. PokerBench: Training Large Language Models to become ... arxiv.org Supports the application to preflop scenarios and the solver-derived nature.
  4. Profit-Maximizing Poker Agents for No-Limit Hold'em arxiv.org Supports the distinction between GTO and broader poker preflop ranges.
  5. arXiv:1302.7008v2 [cs.GT] 7 Mar 2013 arxiv.org Supports the open-raise size of 3 BB.
  6. A Heuristic Framework for Adaptive Poker AI arxiv.org Supports the distinction between GTO and heuristic ranges.

Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.