Double Twist Blackjack is a game I noticed at the Stratosphere in Las Vegas on February 2, 2016. It bills itself as a new game concept, but it is really just blackjack with an optional side bet. For this reason, I am classifying it as a side bet rather than a unique game.
Rules
The game is based on conventional blackjack rules.
There are two betting spots per player.
The player may make a side wager on each betting spot.
The side wager pays based on the player's initial two cards and the dealer's up card.
The pay table is shown below. I presume that the player is paid based on the highest win only.
Double Twist Pay Table
Event
Pays
Three-card royal
50 to 1
Suited three of a kind
35 to 1
Straight flush
30 to 1
Three of a kind
20 to 1
Straight
4 to 1
Flush
3 to 1
Pair
1 to 1
Analysis
The following tables show the probability and contribution to the return for 4, 5, 6, and 8 decks.
Double Twist Return Table — Four Decks
Event
Pays
Combinations
Probability
Return
Three-card royal
50
256
0.000173
0.008659
Suited three of a kind
35
208
0.000141
0.004925
Straight flush
30
2,816
0.001905
0.057148
Three of a kind
20
7,072
0.004784
0.095680
Straight
4
46,080
0.031172
0.124687
Flush
3
85,120
0.057581
0.172744
Pair
1
284,544
0.192486
0.192486
Loser
-1
1,052,160
0.711758
-0.711758
Total
1,478,256
1.000000
-0.055427
Double Twist Return Table — Five Decks
Event
Pays
Combinations
Probability
Return
Three-card royal
50
500
0.000173
0.008634
Suited three of a kind
35
520
0.000180
0.006285
Straight flush
30
5,500
0.001899
0.056983
Three of a kind
20
14,300
0.004938
0.098770
Straight
4
90,000
0.031081
0.124326
Flush
3
168,200
0.058088
0.174263
Pair
1
561,600
0.193948
0.193948
Loser
-1
2,055,000
0.709693
-0.709693
Total
2,895,620
1.000000
-0.046484
Double Twist Return Table — Six Decks
Event
Pays
Combinations
Probability
Return
Three-card royal
50
864
0.000172
0.008617
Suited three of a kind
35
1,040
0.000207
0.007261
Straight flush
30
9,504
0.001896
0.056872
Three of a kind
20
25,272
0.005041
0.100819
Straight
4
155,520
0.031021
0.124085
Flush
3
292,896
0.058424
0.175271
Pair
1
977,184
0.194918
0.194918
Loser
-1
3,551,040
0.708321
-0.708321
Total
5,013,320
1.000000
-0.040478
Double Twist Return Table — Eight Decks
Event
Pays
Combinations
Probability
Return
Three-card royal
50
2,048
0.000172
0.008596
Suited three of a kind
35
2,912
0.000244
0.008556
Straight flush
30
22,528
0.001891
0.056735
Three of a kind
20
61,568
0.005169
0.103370
Straight
4
368,640
0.030947
0.123786
Flush
3
700,928
0.058841
0.176524
Pair
1
2,336,256
0.196124
0.196124
Loser
-1
8,417,280
0.706612
-0.706612
Total
11,912,160
1.000000
-0.032921
The following table summarizes the house edge by number of decks.