Under those conditions, the six-deck game with a 3-2 payoff on blackjacks has a house edge of 0.64 percent against a basic strategy player. With two-decks and a 6-5 payoff on blackjacks, the house edge soars to 1.83 percent. Simple on the surface, card counting is a difficult technique to master. Players find it quite tricky to implement the technique while playing at a casino. That is why a single deck of cards is ideal for card counting among beginners. The fewer the decks, the easier it is for the players to keep the running count and then, finally arrive at the true count. One or two decks allow for better deck penetration, which is one of the primary goals of card counting. When it comes to bet spreads, a spread of 1-8 units is given for double-deck games in the tables below. It is the spread, which would generate the largest profit for the player without immediate notice from the casino surveillance. In the majority of single deck blackjack online free double-deck games the player is able to earn by using a spread as low as 1-4 units. Larger spreads would generate quite decent profits in these games, but it is also quite possible for the player to draw undesired attention to his/her play.