Cards 2-6 count +1, 7-9 count 0, tens and aces count -1. Divide the running count by decks remaining to get the true count.
A European wheel has 37 pockets. An even-money bet wins on 18 of them and loses on 19, so every unit wagered loses 1/37 of a unit on average, about 2.7%. Changing the size of the next bet after a win or a loss changes how the bankroll moves, not where it is expected to end up. The dashed EV line on the chart is the starting bankroll minus 2.7% of everything wagered so far.
| System | After a loss | After a win | Main risk |
|---|---|---|---|
| Martingale | Bet ×2 | Back to base | Losing streak hits table max or bankroll |
| Fibonacci | One step up | Two steps down | Slow, deep drawdowns |
| D’Alembert | +1 unit | −1 unit | Long sessions drift toward −2.7% |
Hi-Lo tracks the ratio of high to low cards left in the shoe. A positive true count means more tens and aces remain, which helps the player. The Card Dojo shows the count live so you can check your own tally, and the EV coach flags any decision that differs from basic strategy.