Martingale

the martingale system in roulette is a system of betting on outside bets on preferably on European Roulette tables (i.e. black/red, even/odd, 1-18/19-36) .

The odds of winning on outside bets are approximately 48% on Single Zero European roulette tables and less on the Double Zero American tables which is why it is essential to play on the European roulette tables.

Basically the idea is to wait till you see a repeat of 3-4+ of the same even bet (i..e 5 reds, or 5 evens) and to bet on the opposite. Althought the odds remain the same, statistically the opposite bet will be due at some point.

Some people however choose to bet the same outside bets as the previous few spins

hen placing a bet and you lose,  and this is the tricky part, you will need to double up your next bet. Let’s say we start betting at £1:

 So despite swinging the odds in your favour, they are still odds and this could result in a significant loss if not played with strict discipline. You must also remember that when doubling up every time when a win does come, your profit will only be that minus your total bets between each win  (e.g when you’ve reached and won £16 you will only be £1 in profit as a result of your previous losses. Multiply those figures by what you initial bet is and you work out your potential losses.

Wikipedia explains the Martingale system in more detail. https://en.wikipedia.org/wiki/Martingale_(betting_system). In fact they consider it a strategy that is highly risky and a losing one in the long term but I believe that only really occurs when you overstay your welcome on the same table.

This is the a very risky strategy and is most definitely not recommended for longterm play and all in all, do so at your own risk!!