Illustrious 18 & Fab 4

There are hundreds of possible deviations, and most of them are worth almost nothing. In 1986 Don Schlesinger identified the eighteen that carry the great majority of the value — the Illustrious 18 — and later the four surrender plays that matter when late surrender is offered, the Fab 4. Together they capture around 80–90% of everything deviations can give you.

The list starts with the four that matter most: insurance at +3, standing on 16 against a 10 at 0, standing on 15 against a 10 at +4, and splitting a pair of tens against a 5 at +5. If you learn nothing else, learn those.

The negative-index plays are the ones beginners forget: at a low count you hit hands that basic strategy stands on, such as 12 against a 4, 5 or 6, and 13 against a 2 or 3. They come up constantly, because low counts are as common as high ones.

The tables below are generated from this trainer's own engine — the same numbers the casino table grades you against, so they cannot drift apart. Indices are for a six-deck game where the dealer stands on soft 17. The Flashcards deviations level teaches every one of them as a situation rather than a line in a list.