Basis21: Blackjack Trainer

New: hit past two cards and see how the hand actually plays out — plus sharper explanations, a mistakes-review mode, and a colorblind-friendly palette.

Basis21 teaches you the mathematically correct play for every blackjack hand — not general tips, but the exact, EV-optimal decision for the specific rules at your table.

HOW IT WORKS • Pick your casino's exact rule set (deck count, dealer soft-17 behavior, doubling restrictions, surrender availability, and more) — Basis21 ships with presets for major casinos and lets you fine-tune any rule. • Drill: get dealt random hands and choose your play. Basis21 grades every decision instantly, shows the correct action and the EV difference if you got it wrong — and with Continue after Hit, you can draw a real card and play the hand one move further instead of stopping at the first decision. • Strategy Chart: browse the full basic-strategy chart for your rule profile, with an EV breakdown behind every cell so you understand why it's correct — not just what to memorize. • Compare: heading to a different casino? Put your usual rules side by side with the table you're about to play — see exactly how many hands change, and by how much, before you sit down. • Track your accuracy over time, see exactly which situations you're weakest on, and drill them directly — with focus modes for your weakest spots, mistakes you've made before, and the genuine close-call hands where the correct play is a coin flip.

WHY BASIS21 Off-the-shelf strategy charts assume one generic rule set. Real tables vary — deck count, dealer soft-17 behavior, doubling restrictions, and surrender rules all shift the correct play. Basis21 computes strategy from first principles for your exact rules, so what you drill is what you should actually do at the table.

Basis21 is a training tool for education and entertainment. It does not involve real-money wagering, betting, or gambling of any kind, and correct basic strategy narrows the house edge — it does not guarantee winning.