The Illustrious 18 and Fab 4
Updated 9 November 2026 · Blackjack Theory
Card counters don’t only change their bets. At certain true counts, the best play itself changes. The Illustrious 18 and Fab 4 are the deviations from basic strategy that matter most. Here they are for a 6-deck shoe, with how to use and learn them.
How index plays work
Basic strategy assumes a neutral deck. As the true count rises, the remaining cards are richer in tens and aces, which makes standing on stiff hands, doubling and splitting tens more attractive. Each index play has a number, the index: at a true count at or above it, make the deviation; below it, play basic strategy. True counts here are rounded toward zero.
For example, 12 vs 3 has an index of +2. Basic strategy says hit, but at a true count of +2 or more, stand.
The Illustrious 18 (6 decks, dealer hits soft 17)
Insurance tops the list: take it at a true count of +3 or higher. The rest, in rough order of value:
| Hand | Index | At or above | Below |
|---|---|---|---|
| 16 vs 10 when you can’t surrender | 0 | Stand | Hit |
| 15 vs 10 when you can’t surrender | +4 | Stand | Hit |
| 10,10 vs 5 | +5 | Split | Stand |
| 10,10 vs 6 | +4 | Split | Stand |
| 10 vs 10 | +4 | Double | Hit |
| 12 vs 3 | +2 | Stand | Hit |
| 12 vs 2 | +3 | Stand | Hit |
| 9 vs 2 | +1 | Double | Hit |
| 10 vs A | +3 | Double | Hit |
| 9 vs 7 | +3 | Double | Hit |
| 16 vs 9 when you can’t surrender | +5 | Stand | Hit |
| 13 vs 2 | −1 | Stand | Hit |
| 12 vs 4 | 0 | Stand | Hit |
| 12 vs 5 | −2 | Stand | Hit |
| 12 vs 6 | −1 | Stand | Hit |
| 13 vs 3 | −2 | Stand | Hit |
With H17, 11 vs ace is already a double in basic strategy, so it never changes with the count.
The Fab 4 surrenders
Where late surrender is offered, these four decisions depend on the count:
| Hand | Index | At or above | Below |
|---|---|---|---|
| 14 vs 10 | +3 | Surrender | Hit |
| 15 vs 10 | 0 | Surrender | Hit |
| 15 vs 9 | +2 | Surrender | Hit |
| 15 vs A | −1 | Surrender | Hit |
If the dealer stands on soft 17
A few indices differ at S17 tables:
- 11 vs A: At +1 or higher, double. Below +1, hit.
- 10 vs A: At +4 or higher, double. Below +4, hit.
- 15 vs A: At +1 or higher, surrender. Below +1, hit.
How to learn them
- Make sure your basic strategy and true count are reliable first.
- Start with insurance and the stiff hands against a 10 (16 vs 10, 15 vs 10), which come up most often.
- Add the 12s and 13s against small cards; their indices are near zero, so they matter at almost every count.
- Finish with the doubles and the ten splits, which only apply at high counts.
- Practise with hands dealt near each index, so you learn exactly where the play flips.
Frequently asked questions
What is the Illustrious 18?
The Illustrious 18 is a list of the 18 most valuable count-based changes to basic strategy, identified by Don Schlesinger. Each one gives a true count (the index) at which the best play switches, such as standing on 16 against a 10 at a true count of 0 or higher.
What is the Fab 4?
The Fab 4 are four late-surrender decisions that depend on the count: 14 vs 10, 15 vs 10, 15 vs 9 and 15 vs ace. They add value at tables that offer late surrender.
Do I need to learn the Illustrious 18 to count cards?
No, betting with the count provides most of a counter’s edge. The index plays add a smaller extra edge, with insurance at +3 the most valuable. Most counters learn them after they can keep an accurate true count.
Do the indices change with the rules?
A little. These indices are for 6-deck Hi-Lo. Where the dealer stands on soft 17, 11 vs ace becomes a deviation (double at +1), 10 vs ace doubles at +4 and 15 vs ace surrenders at +1.