Shaun system is a specific and highly aggressive roulette system. The probability of winning is 9:1.
It's based on the simple fact, specifically that the roulette has 36 numbers + 0. Chips are used to cover 33 numbers and only 4 numbers are left uncovered. Unless one of these 4 numbers hits, you win 6 chips per game. This roulette system is not suitable for long games; I'd recommend 3-4 games.
Bet exactly based on the following scheme:
The total bet is 66 chips.
Shaun system can also be played progressively. This means that if you lose, multiply your bets. But keep in mind that already your first game starts with 66 chips. So even a short streak of bad luck could cost you all your chips. But if you do well, you can quickly get away with a nice win.