Every variant on this page starts from the same pitch: we'll give you something wonderful — free doubles, the right to swap cards, both dealer cards face up — and take back something you won't notice. What they take back is always one of three things: the dealer's bust (a 22 pushes instead of losing), the blackjack bonus (even money instead of 3:2), or the tens (four per deck, gone). The gift is on the felt in big letters. The price is in the fine print. These are not blackjack with a twist; they are different games that borrow the name, and they need their own strategy charts.
Six decks, dealer hits soft 17, blackjack still pays 3:2. The gift: double for free on hard 9, 10 or 11, and split any pair except tens for free — the dealer puts up a lammer for the extra bet, and if you win you're paid on it as if it were your money; if you lose, only your original bet goes. Free splits can be re-split, and you can free-double after a free split. The price: a dealer 22 pushes every hand still standing instead of busting. That one rule is worth about 7% to the house, and the free bets buy back most of it. Net house edge with the right strategy: 1.04%.
The strategy is nearly "take every free bet you're offered", and the chart for the free hands is more aggressive than regular basic strategy because a push costs you nothing on the free money. The mistake players make is the reverse: playing their real-money hands like regular blackjack, where a dealer 22 would have been a win. Against 7 through A you now hit harder totals more often, because standing and waiting for a bust has lost some of its value.
You must play two hands of equal size. After the deal you may swap the second cards between them: 10-6 and 5-A becomes 10-A and 5-6. Any blackjack made by switching is just 21. The gifts are enormous — you turn two stiffs into a twenty and an eleven. The prices: blackjack pays even money, and a dealer 22 pushes all your standing hands. Six decks, dealer hits soft 17: 0.58% with the full switching strategy, which is about the same as ordinary blackjack — except you learned two charts (the switch decision and the post-switch play, which is also more aggressive against 7–A because of the push-22 rule) for the privilege.
The simple switching rule ranks final hands 21, 20, 19, A-A, 11, 10, 9, 18/8 and picks the arrangement with the best hand; against a dealer 7 or 8 you balance the two hands instead. The advanced strategy scores each hand against the upcard and costs 0.08% versus the simple rule's 0.17%. Dealer stands on soft 17 takes 0.30% off; eight decks adds 0.02%.
Six or eight 48-card decks with the four tens removed (the face cards stay). Removing tens is worth about 2% to the house; the rulebook then hands most of it back: player 21 always wins, player blackjack beats dealer blackjack, late surrender, double on any number of cards, double after split, re-split aces and hit them, and "double-down rescue" (surrender the doubled portion after a bad card). Plus bonuses: five-card 21 pays 3:2, six-card 2:1, seven-card 3:1; 6-7-8 and 7-7-7 pay 3:2 mixed, 2:1 suited, 3:1 in spades. House edge: 0.40% with dealer standing on soft 17; 0.42% hitting soft 17 with redoubling; 0.76% hitting soft 17 without it. The best of the family on paper — and the strategy chart is the most different from regular blackjack of any game here, because the multi-card bonuses change when you hit and when you double.
Both dealer cards are dealt face up. That is worth roughly 10% to the player and the game takes it all back: the dealer wins every tie except a blackjack against a blackjack, player blackjack pays even money, and the doubling and splitting rules are usually clipped (split once only; double on 9–11 or 10–11 only). The house edge swings wildly with the fine print: 0.26% at the best-known rule set, 0.66–0.96% at typical ones, 1.47% at the worst. Read the placard before you sit — there is no such thing as "the" Double Exposure edge.
Single deck usually, and a gift basket: late surrender on any number of cards, surrender after doubling, double on any number of cards, a five-card 21 pays 2:1 instantly, six cards totalling 20 or less wins automatically, and a blackjack in diamonds pays 2:1. The price is one line: every other blackjack pays even money. Since blackjacks are 4.7% of hands and the 3:2 bonus is worth 2.3%, that single change costs more than all the gifts give back. House edge 1.16% single deck, 1.30% two decks, 1.40% six decks. Playable; not a bargain.
| Game / rule set (variant's own strategy) | House edge |
|---|---|
| Double Exposure, best-known rule set | 0.26% |
| Spanish 21, dealer stands on soft 17 | 0.40% |
| Spanish 21, hits soft 17, redoubling allowed | 0.42% |
| Blackjack Switch, 6 decks H17, full strategy | 0.58% |
| Double Exposure, typical Atlantic City / Las Vegas rules | 0.66–0.68% |
| Blackjack Switch, simple switching rule | ~0.75% |
| Spanish 21, hits soft 17, no redoubling | 0.76% |
| Free Bet Blackjack, 6 decks H17 | 1.04% |
| Super Fun 21, single deck | 1.16% |
| Super Fun 21, six decks | 1.40% |
| Double Exposure, worst common rules | 1.47% |
| Any of the above played with regular basic strategy | add ~0.5–1.5% |
| Blackjack Switch — Super Match side bet | 2.55% |
| Spanish 21 — Match the Dealer side bet (6 decks) | 3.06% |
| Free Bet — Pot of Gold side bet | 4.64–5.77% |
| Free Bet — Push 22 side bet | 11.76% |
Pick a variant and a rule set. The simulator plays 1,000 sessions from a result shape calibrated to the published house edge (these are labelled approximate — the variants don't have the clean combinatorics of a single bet). Try Spanish 21 against Super Fun 21 at the same unit: same cards, a percentage point apart.
Free Bet and Switch. The count works but pays less: a ten-rich shoe helps the player mainly by busting the dealer, and push 22 removes part of that. Published analyses put the counter's edge at roughly half of what the same count earns at a 3:2 game, though the free bets in Free Bet get more valuable as the count rises (free doubles on 10 and 11 are worth more with tens coming), and some counters specialise in it precisely because the pit isn't watching those tables as closely.
Spanish 21. Counting is legal and possible, but the tens are already gone, so the swings in ten-density are smaller and the bonus rules complicate the index plays; the practical edge is thin. Double Exposure counts about as well as regular blackjack, which is why its doubling rules are usually the most restrictive in the building. Super Fun 21 is single-deck and countable, with the same shallow-penetration defences every single-deck game runs.
Legality and acceptance are identical to blackjack's: your brain is legal, devices are not, and a casino that identifies you will back you off from any game in the family. Hole-carding is off the table at Double Exposure for the obvious reason.