Sharp 21 is the most serious blackjack training app on the App Store. Built for players who want to walk into a casino prepared, not just entertained.

BASIC STRATEGY TRAINER
Master every decision at the table. Select your exact rule set — H17 or S17, DAS, surrender rules, blackjack payout — and drill hands with instant, non-blocking feedback. Every hand plays out completely: you hit, split, double down, the dealer draws, and the outcome resolves. A subtle flash tells you the moment you make a wrong call, but the hand keeps going — just like a real table. After each hand, review exactly what you got wrong and why.

Track your chip balance with flat bets, build accuracy streaks, and let the Mistake Journal pinpoint your weak spots so you can focus where it matters.

CARD COUNTING SIMULATOR
Configure every detail of your practice environment: number of decks, dealer rules, deck penetration, counting checkpoints, base bets, and bet spreads. Choose from preset spreads (Conservative, Moderate, Aggressive, Wong Out) or build a custom spread unit by unit.

Practice maintaining a running count, converting to true count, and sizing your bets correctly — all under configurable casino noise events like early shuffles and pit boss distractions. Toggle the running count display on or off as a learning scaffold.

THE SHARP — ROGUELITE MODE
A roguelite that turns basic strategy decisions into a scoring engine. Earn Chips x Multiplier for correct plays, build Rush streaks for escalating multipliers, and collect from a pool of 46 unique modifiers across draft picks and shop purchases. Beat escalating blinds across shoes, manage risk-reward modifiers like Glass Cannon and Loan Shark, and chase your highest run.

No card counting required — The Sharp is accessible to every player and endlessly replayable.

KEY FEATURES
- Full hand play-out in every mode — hands resolve completely, splits play independently
- Rule-variant-aware strategy engine — not a single static chart
- Non-blocking wrong-decision feedback — learn without flow interruption
- Post-hand decision review with full context
- Post-session analytics: accuracy breakdowns, mistake patterns, chip results
- Mistake Journal with spaced repetition to target weak spots
- Interactive strategy chart viewer
- Fully offline — no account, no internet required
- No ads. No subscriptions. Pay once, own it forever.