The Wrangler's strategy is sometimes also called the Wrangler's march. We would actually call it a system as it comprises of rules for the bet selection, two kinds of betting progressions and a win goal. It was invented by a mathematician and is designed for the even money bets of roulette like Red/Black High/Low and Odd/Even but it may be used also for Baccarat or other games with even chances. The system was published for the first time in 1910 in a book called "Monte Carlo Anecdotes And Systems of Play". The author of the book heard about it from am player in Monte Carlo who allegedly used it successfully over the course of 6 years.
Using the Wrangler march you bet on any one of the even chances until two consecutive losses. Then you switch to betting on the opposite chance. The original user of the system had 2 x 1000 units bankrolls and played a 4-step Martingale with a session win goal of about 20 to 40 units. Martingale Progression: 1, 2, 4, 8. After a lost progression of 15 units he split up the loss into 2 | 3 | 2 | 3 | 2 | 3 and played the same bet selection using the Labouchère betting strategy in an attempt to recoup his loss. If the Labby went to deep which is an overall loss of 50 units he would split it up into two or three Labbys and would continue the game until all Labbys would have been completed. After completion of the Labouchère progressions and winning back the 15 units he lost, he continued to use the Martingale.
In the following example you choose to play High/Low and start following the result of the first spin you see when coming to the roulette table.
|1||11||X||Trigger. You bet on Low.|
|6||33||X||2||-2||-1||Lose. Next bet on High.|
|12||15||X||2||-2||+3||Lose. Next bet on Low.|
|14||27||X||8||-8||-9||Lose. Now you play the Labby on High.|
|16||17||X||7||-7||-21||Lose. Next bet on Low.|
|20||2||X||5||+5||+6||Win. Labby cleared and recovered loss.|
|22||23||X||2||-2||+3||Lose. Next bet on High.|
|23||31||X||4||+4||+7||Win. End session.|
The original system was tweaked and an exception was added to the rules: After two isolated consecutive series of 2 you bet up to three consecutive losses instead of two! This procedure is an attempt to neutralize long alternating series of 2. If you want to try the system with a positive progression then the Guetting Progression would be a good choice.
The combination of a short Martingale Progression and a Labouchère is quite a nice staking method. Mostly the more aggressive Martingale will do its job to make you win steadily. But if you hit a longer losing streak the less aggressive Labouchère tries to keep you in the game and protects your bankroll. The disadvantage of the system is the fact that the longer you play the more likely you are to finally hit a losing streak that you may not be able to sit out without a stop loss limit, even with split Labouchère progressions.
To verify if the assertion made by the original user of the system having won several years can possibly be true we ran a 1000 games test on live dealer roulette. The results support the statements as you can see in the charts below. The end of one game is defined as the moment when 1 unit was gained. Hence 2380 bets were necessary to gain 1000 units profit. The highest bet amount reached 160 units and the longest game took 171 spins in order to gain 1 unit profit. The longest observed losing streaks are 12 spins long and the maximum drawdown was -400 units.