Effect of a Back-Counter (Wonging) on your Play

Awhile back, I commented that I’d leave a table if I thought it was being stalked by a back-counter. (Someone Wonging in at my table.) Thought I’d sim the effect. Ran two sims. First sim had three players. Basic Strategy players in seats one and two and a Hi-Lo card counter in seat three. We are interested in seat three. Second sim was the same, but a fourth player Wonged in at a TC of +4 and left at the end of the shoe. Again, we are interested in seat three. Six decks, five deck penetration. Each player played 150 million Blackjack hands except the back-counter who played 13 million. The attached ribbon chart (link below) graphs the winnings by TC for the Hi-Lo player in each sim plus the back-counter. You will note that the red ribbon (seat 3 in the second sim) and the green ribbon (seat 3 in the first sim) run evenly through the negative TC’s. At about +3, the green player pulls ahead. That is, the Hi-Lo player at the table with the back-counter won less money on positive counts. Overall, he lost about 0.15% advantage.

FIRST CHART - Winnings by TC.

OK, where is the lost advantage? The second chart has two series. The green series is the percentage of hands played by seat three at the back-counter’s table of the hands played by seat three at the back-counter-free table. The chart shows that both seat three players played the same number of hands at negative TC’s, but at positive TC’s, the player disturbed by the back-counter played only 80% as many hands. This is due to the back-counter eating cards in positive TC conditions. So far, no surprise. However, there is another effect. The red series on this chart shows dollars bet instead of hands played. Again, the players at both tables bet the same per TC at negative TC’s. But, at positive TC’s the drop-off in units bet is more severe than the drop off in hands played. Only 75% as many units are bet at high TC’s. That is, the average bet was lower at high TC’s. Why is this? Well, the Hi-Lo player was using camouflage play. The spread was 1-8 on both tables, but the player would never make large hand-to-hand bet increases. Since the back-counter’s interference tended to reduce the length of high TC consecutive hands, and reduced the number of hands dealt per shoe in favorable situations, the Hi-Lo player had fewer opportunities to win enough hands in a row to pump his bet up to the optimum level.

CHART TWO - Hands played and Units bet by TC

This shows an important point about running a sim exactly as you would play. It is not enough to show a simple 1-8 spread since realistic cover play may interact negatively with other characteristics of the sim.

Note: When just looking at the overall advantage, 150 million hands is OK. But, when you break this down into smaller groups of hands (e.g. by TC), then you have fewer hands per situation and need more total hands to give good results. However, there is a short-cut that was used here. All lines were smoothed with a 12 facet cubic B-spline formula. This takes information about neighboring data points (nearer points count more than farther points) and adjusts all points to produce a smoother graph. This requires several hundred million calculations, but that’s only seconds on a Pentium. If you are looking for exact data, this is not valid. But, if you are looking at trends, it is quite accurate and fast. To perform this on a CVSIM chart, double-click on a series (e.g. group of bars, a line, an area). The Format Series dialog box will appear. Click on the Options tab. Then, select a Smoothing formula at the bottom left. Click on Help to get information on the options.

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