Blackjack Basic Strategy, played perfectly in a game with favorable rules, will reduce the edge against you to about one half of one percent, the best odds of any game in the casino.
But still - it's a negative edge. While you can win in the short term on any given day, in the long term that one half percent edge against you will eventually grind you down if you play long enough and frequently enough.
An advanced basic strategy - or what we call Basic Strategy Plus - is necessary for you to step up from being a casual player to being a serious recreational player who has a better chance of winning over the long term.
To reduce the small edge against you with Basic Strategy even further, and at times even turn it into a positive edge in your favor, you simply must pay attention to the cards on the table and develop some sense of the proportion of high cards versus low cards remaining in the deck. This is exactly what a card counter does.
But you don't have to spend the hundreds of hours it takes to become a proficient card counter. You can get a general sense of the proportion of high versus low cards by doing something called "counting the table".
Counting the table simply means that in any given hand, you look at the exposed cards for all hands on the table (including the dealer's hand). Do a quick count of all the high cards (tens, jacks, queens, kings) and all the low cards (2 - 5). There are an equal number of these high and low cards.
If there are a much larger number of low cards showing than high cards (at least 6 more low cards than high cards in a six deck game), chances are that the deck now is slightly richer in high cards, which is favorable for the player. Conversely, if there are many more high cards showing than low cards (again, at least six more), chances are the deck is now slightly richer in low cards, which is bad for the player.
Armed with the information gained from this quick table count, you can now adjust your play accordingly and thus be playing a little more like a professional.
For example, there are some basic strategy moves that are so close that they could go either way. If you are doing a table count, you have additional information that may indicate a change in what basic strategy says to do in certain of these close call situations.
To illustrate, let's take the example of one of the most dreaded hands in Blackjack: your 16 count versus the dealers 10 up card. Basic strategy says to hit your 16 against a dealer's 10, but this is an extremely close call. You very badly need a 4 or 5 in order to tie or win if the dealer also has a 10 card down.
So, using the table count, here's what you do. If the table count shows at least 6 more lows than highs, then stand on your 16 against a 10. A disproportionate amount of low cards have been dealt and this lowers your odds of getting a low card to point where you should now stand with your 16.
There are several more close calls with Basic Strategy that can be refined further with Basic Strategy Plus, as well as other decisions that can now be made more intelligently and these are explained in detail on the author's web site.
Good luck!
