Part III: Business & Regulation · Gambling Mathematics & Probability

32. Wong Halves System

Blackjack Math

The Wong Halves system is a Level 3 balanced card counting system created by Stanford Wong that assigns fractional point values to cards for maximum accuracy. The values are: 5 = +1.5, 3-4 = +1, 2-7 = +0.5, 8 = 0, 9 = -0.5, and 10-Ace = -1. Despite its theoretical advantages (betting correlation of 0.99, playing efficiency of 0.56), the fractional values make it extremely difficult to use in practice, which is why it has not achieved widespread adoption. Some players round the values to integers (+1, +1, +1, +1, +1, +0.5, 0, -0.5, -1, -1) to make the system more practical. Surveillance is unlikely to encounter Wong Halves practitioners in the field.

In practice

Stanford Wong (pen name of John Ferguson) is one of the most influential blackjack authors. His “Professional Blackjack” remains a seminal text. The Wong Halves system, while theoretically optimal, is primarily of academic interest due to its extreme difficulty.

One entry from the Casino Industry Glossary — 1,157 terms written for surveillance, compliance and operations professionals rather than for players. Definitions describe industry usage; where a term carries a regulatory meaning, verify against the instrument that governs your jurisdiction.