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Last Updated: February 2, 2017

Dueling 8's 21

Rules



Dueling 8's 21 is a blackjack variant where both the player and dealer always start with the eight of spades. The game is played with 48-card Spanish decks. It was spotted in late January 2017 by a Wizard of Vegas forum member at the Marina Bay Sands in Singapore.

Rules



The following rules for Dueling 8's 21 assume the reader is already familiar with conventional blackjack rules and terminology.

  1. Eight 48-card Spanish decks are used. A "Spanish deck" is the same as an ordinary 52-card deck with the four 10's removed.
  2. All cards are scored as in blackjack, meaning:
    • 2-9 = Pip value.
    • Face cards = 10 points.
    • Aces = 1 or 11 points, whichever is more beneficial to the hand.

  3. Play shall start with the player making a wager. In additional to the required game wager, the player may make an optional "Superb 8's" side bet.
  4. Both the dealer and player shall start their hands with an eight of spades imprinted on the felt.
  5. The playing out of the hand is the same as in blackjack.
  6. Surrender is allowed on the initial two cards only.
  7. The player may double on any two cards, including after splitting.
  8. The player may split only if his first two cards are eights, including the 8 of spades he automatically starts with.
  9. The player may re-split to up to four hands.
  10. Conventional blackjack rules follow for determining the winner.
  11. If the player achieves a hand of 6-7-8 (including the starting 8) on the initial hand, then he shall be paid a bonus equal to his wager, except a 6-7-8 in all spades shall pay a bonus of 5 to 1.
  12. The Superb 8's pay table is below. It is based on the number of consecutive 8's in the player's hand, including the starting eight of spades. The win for three eights can be achieved with either an 8-8-8 single hand or through a split followed immediately by a re-split.


At the Marina Bay Sands the game is dealt from a continuous shuffler.

Superb 8's Pay Table

Event Pays
Four 8 of spades 8000 to 1
Four 8's 800 to 1
Three 8's 8 to 1
Two 8's 3 to 1


Strategy



The strategy is the same as in blackjack, despite the lack of 10's in the deck. Here is the strategy:

  • Always split 8's.
  • Double 10 or 11.
  • Hit 12 to 16.
  • Stand on any 17 to 21.

If you prefer my basic strategy charts, I think this is the smallest one I've ever made.



Analysis



The following table shows the frequency of each net win per initial bet from a simulation of about 25.3 billion hands. The lower right cell shows a house edge of 1.07%.

Base Game Return Table

Net Win Count Probability Return
8 12,044 0.00000048 0.00000381
7 193,122 0.00000764 0.00005345
6 21,938,898 0.00086746 0.00520475
5 9,762,891 0.00038602 0.00193011
4 38,456,255 0.00152055 0.00608220
3 179,374,100 0.00709241 0.02127723
2 2,815,350,834 0.11131829 0.22263658
1 7,120,639,473 0.28154836 0.28154836
0 3,866,888,489 0.15289583 0.00000000
-1 8,872,166,127 0.35080329 -0.35080329
-2 2,141,871,573 0.08468908 -0.16937816
-3 167,691,189 0.00663047 -0.01989141
-4 47,626,418 0.00188314 -0.00753255
-5 7,467,888 0.00029528 -0.00147639
-6 1,406,765 0.00005562 -0.00033374
-7 143,952 0.00000569 -0.00003984
-8 9,982 0.00000039 -0.00000316
Total 25,291,000,000 1.00000000 -0.01072206


The bonuses contribute 1.74% to the return. The standard deviation of the base game is 1.283.

The following table shows my analysis of the Superb 8's side bet. The lower right shows a house edge of 17.04% (ouch!).

Superb 8's Return Table

Event Pays Combinations Probability Return
Four 8 of spades 8000 336 0.000006 0.047845
Four 8's 800 29,424 0.000524 0.418985
Three 8's 8 349,184 0.006215 0.049722
Two 8's 3 4,302,848 0.076588 0.229765
All other -1 51,499,712 0.916667 -0.916667
Total 56,181,504 1.000000 -0.170350







Written by: Michael Shackleford

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