I personally recommend using the Red Seven or KO Count card counting systems. They are basic systems that perhaps are the second easiest to learn. By using an easy system you sacrifice some potential advantage. However, a simple system counted correctly is better than an advanced system played incorrectly. Plus, with a simply system you can play a fast paced game, playing more hands per hour. All statistical advantages require time to bear fruit, so the more hands you play the better.
So what is the easiest system? That is the Wizard Ace/Five count system. Be warned, it is easy but not for the faint of heart. It attempts to counter the accuracy loss by using large bet spread. Any card counter must increase his bet when the odds are in his favor in order to beat the house. The difference between the minimum wager (played when at a disadvantage) and the maximum wager (played when at the maximum statistical advantage) is the bet spread. The Wizard Ace/Five count has a maximum bet potentially as high as 38 times the minimum. That means if you a $10 minimum, you must be prepared to wager up to $380 on a single hand. You must also have the bankroll to support that high of a spread.
Card counters are normally identified by their bet spread. With such a large bet spread, you may think the Wizard Ace/Five count may quickly get you spotted as a counter. On the contrary, the Wizard Ace/Five system is so basic; you are unlikely to get identified as a counter.
In addition, the Wizard Ace/Five offers little advantage. The system can be used recreationally just to gain comps from sustained playing time, but will offer little value beyond that.
So what is the Wizard Ace/Five? The system uses only 2 point values. Any five card played is +1. Any ace played is minus one. That’s it. You keep a running count starting at 0 and looking for fives and aces only. In addition, there is no “true” count, so you do not need to divide the running count by the number of decks remaining. With a 75% penetration, stand on soft 17, late surrender and re-splitting aces you can get a 0.22% advantage using the recommended bet spread.
The five card is an important card because it will not bust the dealer hitting a 16 and makes a 17 out of 12. Therefore the five is important. The ace on the other is beneficial to the player. Ace and Shuffle tracking exist just to track aces.
Now the painful bet spread. You bet the minimum wager on any zero or negative running count. For a positive count, you bet 2 times the minimum times the running count. This can potentially lead to a spread of 38 times the minimum assuming a six deck shoe. If you were to assume that all fives were played (4 cards per deck and 6 decks per shoe) and no aces played, the highest bet could be 48 times the minimum (24 x 2). I have heard that in simulations of a billion hands, the spread never actually got higher than 38 times. You must bet the proper spread in order to take advantage of the positive signal. Reducing the bet spread reduces your edge. The average bet in simulation is 2 to 3 times the minimum wager.