How casino blackjack rules evolved

Every significant change to casino blackjack since 1962 has moved the house edge, and nearly all of them have moved it the same way. The single-deck, hand-dealt, dealer-stands-on-soft-17 game of the old Las Vegas Strip gave a basic-strategy player close to break-even; the typical modern Strip game, six or eight decks, dealer hits soft 17 and blackjack paying 6:5, costs the same player around 2%. The figures below are published effects on the player’s expectation, attributed to Wizard of Odds and BlackjackInfo; positive numbers favour the player.

The baseline: hand-dealt single deck

Las Vegas blackjack in the 1950s and 1960s was dealt by hand from one deck, often to the last few cards. Anthony Curtis, quoted by Las Vegas Advisor, calls “the old Las Vegas game” the best standard game ever offered: single deck with a player edge of 0.04% under basic strategy. Those rules, often called “old Las Vegas Strip rules”, included the dealer standing on soft 17, doubling on any two cards and a 3:2 natural.

That game was the environment Thorp analysed in Beat the Dealer. Deep single-deck dealing is exactly what makes counting most powerful, because every card seen is a large fraction of what remains.

More decks

The first countermeasure was more cards. easy.vegas’s trend summary records that after Thorp’s 1962 book “casinos immediately began taking countermeasures”, the first being extra decks; Las Vegas Advisor’s account of the 1980s Strip says multi-deck shoes “became more common over the period as a response to card counting”, though single- and double-deck games were still common on the Strip then.

The jump from one deck to two is the largest; six to eight barely registers. The real cost of a shoe to a counter is dilution: a seen card from six decks carries one sixth of the information it would in one, and the cut card stops the deal before the richest part of the pack. See single versus multi-deck and how a shoe game is dealt.

Doubling and splitting restrictions

Las Vegas Advisor lists “restrictions on doubling down and splitting” among the countermeasures that followed Beat the Dealer, alongside extra decks and earlier shuffles. The published costs are modest individually:

Figures from Wizard of Odds, relative to its eight-deck baseline. See double and split rule variations.

Surrender: early, late and gone

Surrender, giving up half the stake instead of playing the hand, has the strangest history of any rule. When Atlantic City opened in 1978, Tommy Hyland recalls, the rules were “early surrender and hit soft 17 on a 4-deck game at Resorts and a 6 deck games at Caesars” (Las Vegas Advisor). Early surrender means the player can surrender before the dealer checks for blackjack, so a hard 16 against an ace can be abandoned even when the dealer has a natural. Wizard of Odds values it at +0.39% against an ace and +0.31% against a ten, enough, combined with the other rules, to make the game beatable by basic strategy alone for a careful player. The New Jersey Casino Control Commission repealed early surrender in 1981 (Arnold Snyder, Las Vegas Advisor).

Late surrender, offered only after the dealer has checked for blackjack, returned to Atlantic City on 16 January 1990 after the Claridge ran a 90-day trial and petitioned the Commission. Its value is small: Wizard of Odds gives +0.08% against a ten, and Snyder’s simulations put it at under 0.1% for a basic-strategy player and 0.15–0.20% for a counter. Where it is offered at all, it is late surrender; our surrender guide covers the decisions.

Hitting soft 17

The dealer rule on soft 17 is the clearest regional story. In the 1980s, Strip dealers “stood on soft 17” while downtown Las Vegas dealers hit it, which Las Vegas Advisor describes as “a bit more restrictive”. Snyder’s later column says “these days you almost have to play in games where the dealer hits soft 17, as most casinos have adopted this policy”, and prices it: “Hitting soft 17 increases the house edge by 0.22%”. For a $10 bettor at 50 hands an hour that is roughly $1.10 an hour, which is why casinos adopted it and why most players never noticed. The rule changes a few basic-strategy decisions; see H17 vs S17. Our own trainer assumes S17.

6:5 blackjack

Cutting the natural payout from 3:2 to 6:5 is the single most expensive change in the game’s history. Wizard of Odds puts it at −1.39% and BlackjackInfo at +1.36% to the house; Wikipedia notes that only even money, at about 2.3%, is worse. On a $10 bet a natural returns $25 at 3:2 ($10 stake plus $15 profit) but $22 at 6:5 ($10 stake plus $12 profit).

The origin is disputed in detail but not in substance. Arnold Snyder, writing for Las Vegas Advisor, says 6:5 “never existed on any blackjack games prior to 1999”. Howard Grossman, a former counter, had patented Super Fun 21 that year, a variant paying most naturals even money with compensating bonuses; two casino executives, Bill Bert and Bill Zimmer, proposed simply paying 6:5 on an otherwise unchanged single-deck game, which added about 1.4% to the house edge “without the licensing fee”. The Flamingo was the first Strip casino to offer it, starting with one table. easy.vegas tells the same story with the same names and casino but dates it to 2003. Both agree on what followed:

A single-deck 6:5 game is worse for the player than an eight-deck 3:2 game by more than a full percentage point. The arithmetic is in 6:5 vs 3:2.

Continuous shuffling machines

A continuous shuffling machine (CSM) returns played cards to the shuffler after every round, so there is never a depleted pack to count. Wikipedia’s card counting article says CSMs “result in very shallow penetration, greatly reducing the effectiveness of card counting”. The per-hand effect is counter-intuitive: Wizard of Odds appendix 10 shows a CSM “actually lowers the house edge” compared with a cut-card game, by 0.113% in single deck, 0.063% in double deck, 0.020% in six decks and 0.014% in eight. The catch is tempo. Because the dealer never stops to shuffle, more hands are dealt per hour, and for a basic-strategy player “this will result in a greater expected loss on an hourly basis”.

Side bets

Side bets are the newest layer and the most expensive per unit bet. Wizard of Odds says Over/Under 13 bets “have been around since the 1980’s at least” and are probably among the first; the house edge is about 6.5–6.8% on Over 13 and about 10.1% on Under 13 depending on decks. Lucky Ladies, which “started in Washington state”, carries a house edge of 24.71% on its six-deck pay table A. Side bets leave the main game’s edge untouched; they raise the average loss per round without changing the placard. Side bets explained covers the common ones.

Adding it up

All assume a perfect basic-strategy player. The spread from first row to last is about 2.1 percentage points, every step a casino decision made after 1962. None of it is hidden: deck count, soft-17 rule and payout are on the placard, and choosing a table is mostly a matter of reading it.

Related reading

• How rule variations change the house edge
• 6:5 blackjack vs 3:2
• Edward Thorp and Beat the Dealer
• Choosing a table