The number of decks in a Blackjack game affects strategy by changing the odds and probabilities of certain outcomes. With fewer decks, like a single or double deck, the player has a better chance of drawing high cards, which makes strategies like card counting and doubling down more effective. It also slightly lowers the house edge. In contrast, more decks, such as in a 6 or 8-deck game, dilute the effectiveness of these strategies, as the probabilities of drawing favorable cards are reduced. While basic strategy adjustments are minor, fewer decks tend to favor the player by increasing the likelihood of favorable situations like dealer busts or hitting a blackjack. More decks, however, make it harder for players to take advantage of such situations and slightly increase the house edge. In general, games with fewer decks offer better odds for the player, but the impact on strategy is more pronounced for advanced players using techniques like card counting.