There's a real crisis developing for fans of casino blackjack. Many casinos in the US have begun introducing a rule change that dramatically increases the house advantage in the game. If you've been to Las Vegas lately, you may have seen signs advertising "Single Deck Blackjack" at many of the casinos on the Las Vegas strip.

But there's a catch. Look out for a sign on the table that says "Blackjack Pays 6:5". In a normal blackjack game, a "natural" or blackjack pays 3:2. If you bet $10 and draw a blackjack, you'll be paid $15. However, at these new 6:5 games, a $10 blackjack wins only $12.

The casinos have so far been successful in marketing this game, because many occasional players have been told over the years that single deck blackjack is a better game than the more common 6 or 8-deck games on the casino floor. Using that single marketing angle, the casinos have drawn lots of players to the new 6:5 version, despite the fact that these single-deck games are worse for the player than the worst 8-deck game on the casino floor. Much worse.

Changing that one rule, reducing blackjack payouts from 3:2 to 6:5 adds a substantial 1.39% to the casino's advantage. 

Consider this example from the Flamingo on the Las Vegas Strip: They offer a single deck 6:5 game, where the house edge for a basic strategy player is 1.45%. (Like most of these 6:5 games, they allow double after split, which doesn't nearly compensate for the poor 6:5 rule.) They also offer an 8-deck game where the house edge for a basic strategy player is 0.56%. So, a player who chooses their single-deck offering has almost triple the expected loss of a player at their 8-deck game.

What's the difference in actual dollars? For a $25 player, assuming 80 hands per hour, the expected loss at the Flamingo's 8-deck is $11.20 per hour. The expected loss for the same player at the 6:5 single deck game is $29.00 instead. And, remember, this is compared to the game that was previously the worst blackjack in the house!

What can you do to help?

• Don't play any blackjack game that pays less than 3:2 for a blackjack.
• Warn your friends and family if they're headed to the casino. Tell them to play the multi-deck "shoe" games instead.
• Let the casino floorperson at your favorite casino know that you hate to see the casino floor filled with misleading games instead of real blackjack.
• If you have a casino host, let them know your displeasure as well.