Gambling terms, explained straight

Advantage Play & Game Integrity

KO card counting

KO card counting is a blackjack system that assigns point values to cards and keeps a running count to judge when the deck favours the player or the dealer.

Card values
2–6 = +1, 7–9 = 0, 10–A = −113
Starting count
0 at the start of the deck or shoe23
Player edge
Card counting can give the player an edge of up to about 2%4

Key points

  • A higher running count means more low cards have been played, leaving a deck richer in high cards that favours the player.12
  • The running count is divided by the number of decks remaining to get a true count for betting and play decisions.23

Where this term is used

Not the same as

  • Card counting — the broader category of methods that track exposed cards in blackjack, not the specific KO system's tag structure12
Advantage play Card counting The general category of methods that track exposed cards in blackjack. Advantage play Blackjack card counting The practice of tracking cards in blackjack to gain an advantage. Advantage play Card counting machine A device used to automate card counting, distinct from manual systems like KO. Advantage play Hi-lo card counting Another blackjack counting system, similar to KO but with a different starting count and true count calculation. Advantage play Card counting machine blackjack A machine specifically for blackjack card counting, not a manual system. Advantage play Blackjack odds with card counting Blackjack odds with card counting describes how a player can gain a statistical edge by tracking the ratio of high to…

Sources

  1. Card counting en.wikipedia.org Provides the definition and card tag values for KO card counting.
  2. Card Counting in Blackjack - Introduction & Basics wizardofodds.com Explains how the running count and true count work in KO.
  3. 高低牌算牌策略介紹 wizardofodds.com Confirms the card tag values and the process of converting to a true count.
  4. Blackjack - Wikipedia en.wikipedia.org Supports the general player edge figure for card counting in blackjack.

Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.

Written and maintained by Ellis Warrender, writer and maintainer.

Last updated 28 July 2026. Spotted an error? Tell me and it gets fixed and logged on the corrections page.