A lot of blackjack players will fall back on what was once a pretty standard way of playing your hand: play as if the dealer’s hole card is worth 10. This was seen as a way to play with the worst case scenario. No one ever questioned this so-called blackjack strategy, not even when it was noticed that the professional players did not play this way. People shrugged it off and assumed they had some highly intense blackjack strategy.
But this was until checking out the math and probability of cards and hands and rules became more common place. Or until players wanted to became more prudent and wiser in how they played out their hands. It was then that the probability of that hole card being worth 10 became known.
There is only a 31% chance that the dealer’s hole card will be worth 10, as compared to the 69% chance it could be worth any other value.
This prompted a wake-up call among blackjack players. They began to question why they were playing their hands out based on an idea that only had a 31% chance of happening. It seemed kind of silly. And it is. Now they knew why the professional blackjack players never played on the assumption that the hole card was a 10.
This is when basic strategy really took off, and I mean really. It offered players a better strategy, one that was sounder and offered a better house edge: 0.5%. And since then the only players who play blackjack on the assumption that the dealer’s hole card is worth 10 are those who are still new to the game; but they are pretty quick to learn this is not a sound blackjack strategy. They join the rest of us playing on the 69% probability that the hole card is worth something else. In other words they join the rest of us playing according to basic strategy.