Protocol 21:
The Pro Blackjack Trainer App.
Master the count and beat the house. The ultimate Blackjack Card Counting App built for serious advantage players. Casino-grade drills. A definitive 6-Phase Guided Training regimen. Your edge starts here.
Supported Systems
Don't just learn to count. Master the industry-standard Hi-Lo system through 6 rigorous training phases, and explore resources for advanced methodologies.
Hi-Lo
Master the famous Hi-Lo card counting system with Protocol 21. The world's most popular balanced counting system, explained and trained with casino-grade drills for iOS and Android.
KO (Knock-Out)
Learn the KO (Knock-Out) card counting system — the easiest way to gain a casino edge without true count math. Protocol 21 is the best KO trainer app for iOS and Android.
Omega II
Master the Omega II card counting system — the most accurate Level 2 system for professional blackjack. Protocol 21's advanced drills support multi-value card counting and Ace side counts.
Zen Count
Master the Zen Count — a powerful balanced Level 2 system for serious blackjack players. Protocol 21 provides the custom multi-value drills you need to run Zen Count at casino speed.
Red 7
Learn Arnold Snyder's Red 7 system — an easy unbalanced count that removes true count math. Protocol 21's color-sensitive drill mode makes Red 7 the easiest system to learn on mobile.
Wong Halves
Master Wong Halves — the most powerful and most difficult card counting system ever developed. Protocol 21 is the only app that supports fractional half-value drills for expert-level training.
Advanced Drills
Purpose-built exercises that target your weakest skills and transform them into strengths.
True Count Conversion
Target: Mental Math
“dividing the running count by decks remaining instantly under casino pressure”
Deck Estimation
Target: Visual Accuracy
“accurately guessing how many decks remain in the discard tray without looking obvious”
Speed Count
Target: Reaction Time
“losing the running count when the dealer speeds up or multiple cards hit the table simultaneously”
Ready to Get Your Edge?
Join thousands of advantage players who trust Protocol 21 for their training. Start your journey to consistent profits today.
Built for Serious Players
Protocol 21 isn't another blackjack game. It's a professional-grade training system designed by advantage players, for advantage players.
- Casino-accurate dealing speeds
- Background noise simulation
- Detailed accuracy analytics
Frequently Asked Questions
Common questions about card counting and Protocol 21.
What is card counting and is it legal?
Card counting is a legal blackjack strategy that involves tracking the ratio of high to low cards remaining in the deck. It's not cheating—it's using your brain to gain a mathematical edge. While legal, casinos may ask skilled counters to leave as they're private businesses.
Which card counting system should I learn first?
We recommend starting with the Hi-Lo system. It's the most widely used, well-documented, and offers an excellent balance of simplicity and effectiveness. Once you've mastered Hi-Lo, you can explore more advanced systems like Omega II or Wong Halves.
How long does it take to learn card counting?
With consistent daily practice using Protocol 21, most users develop basic Hi-Lo proficiency in 2-4 weeks. Achieving casino-ready speed and accuracy (counting at 1+ cards per second with 99% accuracy) typically takes 2-3 months.
Is Protocol 21 really free?
Yes! Protocol 21 is free to download with core features including Hi-Lo training, basic drills, and shoe simulation. Pro features like advanced systems and detailed analytics are available with an optional subscription.
What's the difference between running count and true count?
Running count is your cumulative total of high/low cards seen. True count normalizes this by dividing by decks remaining (Running Count ÷ Decks Remaining). True count is essential for accurate betting in multi-deck games.
Can I practice card counting on my phone?
Absolutely! Protocol 21 is available for both iOS and Android. Mobile practice lets you train during commutes, breaks, or whenever you have a few minutes. Consistent daily practice is key to building automatic counting skills.
Have more questions?
Read our comprehensive guides