Doublet Blackjack

Introduction

Doublet Blackjack is a unique variant of blackjack developed by Gamesys N.V., a software provider for online casinos. Its distinct rules make it deserving of a dedicated discussion.

Rules

Conventional blackjack Here are the specific rules that must be adhered to:

• Six decks.
• There is no dealer hole card. If a player chooses to double or split and the dealer ends up with a blackjack, the player loses all amounts wagered.
• Dealer stands on soft 17.
• Players have the option to double down on any two initial cards, even after they have split their hands.
• Players can re-split their cards up to four hands, including aces.
• No surrender option is available, except immediately after doubling (refer to the next rule).
• The Double Down Rescue rule is in effect, allowing a player to surrender their hand after doubling, unless that doubling would cause them to bust.

Strategy

The table below outlines the basic strategy.

Here's how the double down rescue strategy works:

• Surrender 16 or less against an 8, 9, 10, or ace.
• Surrender 17 against an ace.

Analysis

Based on my calculations, the house edge for Doublet Blackjack stands at 0.38%.

Side Bets

There are two side bets, as follows.

The first type of payout occurs on a player blackjack, paying out at 19 to 1, with a winning probability of 4.75% and a house edge of 5.02%.

The second payout is known as 'Sevens,' where the reward is contingent on the number of consecutive sevens drawn by the player, starting with their first card. When splitting two sevens, the payout is calculated as two individual sevens, irrespective of the subsequent cards. The accompanying table displays the probabilities and returns for different scenarios. The bottom right cell indicates a house edge of 4.09%.

This table is based on the assumption that a player will consistently hit two sevens and does not factor in the potential drawbacks of straying from the basic strategy in situations against the dealer's cards ranging from 2 to 7 when a split would be the optimal play.

Zero House Edge

There is also a variant of the game dubbed 'Zero House Edge,' which only differs in the payout of a winning blackjack in spades, which pays 2.5 instead of 1.5. The probability for this outcome is 0.30%, thus reducing the house edge accordingly. Consequently, the adjusted house edge for this version amounts to 0.38% - 0.30% = 0.08%.

As with all Gamesys 'Zero House Edge' games, players will incur a 10% commission on any net winnings accrued during a session. A 'session' concludes either after a one-hour break in betting or 24 hours, whichever comes first.

External Links

Doublet Blackjack rules at BetVoyager.com.

Written by: Michael Shackleford