Counting System · Level 1

The KO (Knock-Out) Card Counting System

By VectorLogic · Updated October 2026

KO is a Level 1 count that skips the true count. It counts 7s as +1, starts below zero, and lets you bet straight off the running count. That removes the hardest mental step at a live table.

KO at a glance
Level	1 (every tag is +1, 0 or −1)
Balanced	No. A full deck counts to +4
True count needed	No
Betting correlation	0.98
Playing efficiency	0.55
Insurance correlation	0.78

KO card values

KO card tag values
Cards	Tag	Difference from Hi-Lo
2 · 3 · 4 · 5 · 6 · 7	+1	The 7 counts +1 (it is 0 in Hi-Lo)
8 · 9	0	Same
10 · J · Q · K · A	−1	Same

Why KO starts below zero

With 7s counted, each deck has 24 cards tagged +1 and 20 tagged −1, so the count drifts up by 4 per deck as the shoe is dealt. Starting at 4 − (4 × decks) offsets that drift: 0 for one deck, −20 for six. The result: the pivot is +4 at any shoe size, and you never divide by decks remaining.

Starting count, key count and pivot

You need three numbers for your shoe size, all from the KO book (Vancura and Fuchs):

KO reference counts for 1, 2, 6 and 8 decks
Shoe	Start at	Key count	Pivot
1 deck	0	+2	+4
2 decks	−4	+1	+4
6 decks	−20	−4	+4
8 decks	−28	−6	+4

Start at: your running count right after the shuffle.
Key count: from here the shoe favours you. Start raising your bet.
Pivot: a running count of +4 is roughly a Hi-Lo true count of +4, whatever the depth. Bet your top units here.

Betting with KO

Counting Edge's default KO ramp for a 6-deck shoe:

KO bet ramp for 6 decks
Running count	Bet
Below −4	1 unit
−4 (key count)	2 units
+4 (pivot)	4 units
+8	8 units
+12 and above	12 units

For other shoes, start the 2-unit bet at that shoe's key count instead (+2 for 1 deck, +1 for 2 decks, −6 for 8 decks); the higher steps stay the same.

Playing decisions

Most KO players use plain basic strategy and let the count drive their bets only. Counting Edge shows the key count and pivot for your shoe instead of true-count index plays.

KO or Hi-Lo?

Choose KO if dividing by decks remaining slows you down or causes mistakes. Choose Hi-Lo if you want the most published index plays and true-count accuracy at any shoe depth. The full comparison is on Hi-Lo vs KO.

Where KO came from

Olaf Vancura and Ken Fuchs introduced KO in their 1998 book Knock-Out Blackjack, written for players who found the true count conversion the hardest part of counting.

Sources

KOCountingSystem.kt in the Counting Edge source: KO tag values
CountingSystemProfile.kt in the Counting Edge source: bet ramps, starting counts and key counts
Olaf Vancura and Ken Fuchs, Knock-Out Blackjack
How this site's figures are checked: About

Frequently asked questions

Why does KO start below zero?

KO counts 7s as +1, so a full deck adds up to +4 instead of 0. Starting at 4 − (4 × decks) offsets that, which puts the pivot at a running count of +4 in every shoe.

Is KO less accurate than Hi-Lo?

Not by much. KO's betting correlation is 0.98 against Hi-Lo's 0.97. Hi-Lo's edge is practical: it has far more published index plays, and the true count keeps them accurate at any shoe depth.

Can I use KO with a true count?

You can, but it defeats the point. KO is designed so the running count alone tells you when to raise your bet.

Practice on Android

Practice KO With the Right Starting Count

Counting Edge sets the KO starting count, key count and pivot for your shoe size, tracks the running count as you tap cards, and sizes your bet. Free and open source.

Download APK — Free