Test of a Blackjack Computer’s Betting Efficiency
Letter from Dr. Data Fehnworp
(From Blackjack Forum Vol. XIV #4, December 1994)
© Blackjack Forum 1994
I’ve had a hands-on demonstration of the Perfect Play Blackjack Computer advertised in recent issues of Blackjack Forum. The computer is a Z80 (old 8-bit microprocessor) on a 3 x 3 printed circuit board incased in plastic. Another chip on the board looks like it might be the voice chip. There only appears to be 16k RAM on board.
Anyhow, I had the seller set up Thorp’s classic 100% advantage deck remainder: two 7s and three 8s. The computer came up with a NEGATIVE bet recommendation, but proceeded to make the correct (stand) strategy recommendation. Same thing for two 7s and four 8s.
The vendor seemed surprised at the negative bet recommendation. For the record, in order for a blackjack computer to come up with the “perfect” bet recommendations for any deck residue, it would have to probabilize all player and dealer cards, along with every possible course of action for the player using a binary tree type program. This is essentially recreating Thorp’s “arbitrary subset” program in real time on every hand!
The price of the Perfect Play Computer is $10,000. The $4,000 quoted in the ad is for a lend/lease arrangement. The blackjack computer was hooked up to a speaker for the demo. The quality of the “speech” was only adequate for the purpose, I suppose. The earphone is practically invisible when inserted far down close to the eardrum. There are no wires going to the earphone; the user must wear a transmitter at chest level.
Input was through four spring switches that can be placed anywhere in your shoes for maximum accuracy and comfort. The values of the cards are repeated to the user as they are input. This is an important, user-friendly feature.
Betting Efficiency vs. Betting Correlation with the Perfect Play Blackjack Computer
Snyder Responds: It is my understanding that the Perfect Play computer uses Keith Taft’s old “David” chip, enhanced with the audio output. This computer was also bootlegged for many years under the name “Casey.” As such, its negative bet recommendations on the hands you described would be expected.
This blackjack computer was designed to play perfectly (or close to it), but bets are determined using Thorp’s Ultimate count, a single parameter point counting system described in Beat the Dealer (Random House, 1962/66). Thorp’s Ultimate count has a 100% betting correlation, but this is not the same thing as 100% betting efficiency.
No single parameter card counting system has 100% betting efficiency, and no concealable blackjack computer that I know of has ever been developed that could utilize an arbitrary subset program to analyze betting opportunities with perfect accuracy. This would be so time consuming that it is impractical. Other than for deep single-deck betting situations, it would also be pretty worthless.
Thanks for the first-hand product report.
To read more about blackjack computer card-counting and shuffle-tracking play, see the Interview with Keith and Marty Taft. ♠