A shoe cut at 75% penetration deals three quarters of its cards before shuffling. Deeper penetration means the remaining composition is more predictable, which matters enormously to a card counter and not at all to anyone else.
Casinos manage penetration as their main defence against counting, along with continuous shuffling machines that eliminate it entirely by returning cards to the shoe as they are played.
Basic strategy is unaffected. The decisions on a strategy chart are correct regardless of how deep the shoe is dealt, because they are computed against the full distribution rather than a remaining one.
Continuous shuffling machines are the modern answer and they change the game in a way worth noticing. By returning played cards to the shoe they remove penetration entirely, which defeats counting completely and also speeds the game up by removing shuffle breaks. More hands per hour at the same edge means a higher cost per hour for every player at the table.
Where the numbers come from
Related terms in casino floor
- Commission — A percentage charged on winning bets that would otherwise favour the player.
- Push — A tie in which the bet neither wins nor loses and the stake is returned.
- Natural — A hand that wins immediately on the first cards dealt.
- Shoe — The box holding several shuffled decks from which cards are dealt.
- Cut card — A coloured plastic card placed in the shoe to mark where dealing stops.
- Comp — Complimentary goods or services given to players based on tracked play.
Where an entry quotes a number, that figure comes from the computed sections of this site rather than from another glossary, so the definition and the derivation cannot drift apart. Each entry links to the page where the number is worked out.