Where the numbers come from

There is a lot of blackjack advice on the internet and some of it is wrong. This page is the answer to the only question that should decide whether you trust a trainer: where did it get its numbers, and what happens when it does not have them.

Every number is traced to a source

The chart cells, the Hi-Lo tags, the index plays and the drill benchmarks all come from a single research document, and each numeric claim in it carries the URL it came from. The primary sources are the Wizard of Odds multi-deck strategy and Hi-Lo pages, QFIT’s system comparison tables, Blackjack Apprenticeship’s Hi-Lo guide, and Don Schlesinger’s Blackjack Attack for the Illustrious 18 and the Fab 4.

The code cannot drift from the sources

Being able to cite a chart is not the same as shipping it correctly. The test suite transcribes the charts independently from the research document and compares them to the engine cell by cell. If a number in the code and a number in the research ever disagree, the build fails. Nobody has to remember to check.

The same engine that grades your hand is the one that generates the tables on this site. The chart you read on the strategy page is not a copy of the chart the trainer marks you against — it is the same data, printed at build time.

What it teaches, and in what order

Basic strategy

The complete 6-deck S17 chart — hard totals, soft totals and pairs, 280 cells in all. You play full rounds, then every decision in the round is graded against the chart and explained.

Hi-Lo card counting

2 through 6 count +1, 7 through 9 count 0, tens and aces count −1. Drilled as tag speed, then a full deck countdown, then the true count — the running count divided by the decks still to come.

The Illustrious 18 and the Fab 4

22 index plays with Hi-Lo true-count thresholds, insurance included. Learned as spaced-repetition flashcards, then played live at the integration table.

What is deliberately missing

• H17 index numbers. The deviation table is derived for a dealer who stands on soft 17. Several indices shift under H17 and a sourced H17 set has not been found, so an H17 game turns deviations off with a notice instead of applying the wrong numbers.
• The exact rungs of the bet ramp. The 1–15 spread and the table-minimum-at-low-counts rule are sourced; the individual steps between them are a convention. The trainer shows you the ramp it is grading against rather than presenting it as settled.
• Other rulesets. The engine is rules-aware, but a ruleset is only offered once its numbers are sourced.

Your data

You can use the whole trainer without an account, and if you do, everything it knows about you — which cells you have mastered, your accuracy heatmap, your settings — is stored in your own browser and never leaves it. Nothing is gated behind signing in.

Signing in with Google adds one thing: a copy of that same progress on the server, so it survives clearing your browser and appears on your other devices. No password is created, because Google does the identifying. The full list of what is stored, and how to delete it, is on the privacy page.

What this is not

This is practice software for a card game. There is no wagering, no real money, no prizes and nothing to buy. Counting cards is legal, and casinos are private property that may bar you for doing it well. Nothing here is a betting system, and there is no strategy in blackjack or anywhere else that makes a losing session impossible.

Corrections are welcome, particularly to a number.

Start training The dashboard picks up wherever you left off.