Cut card placement gets discussed in adjectives. A shallow game is poor, a deep one is good pen. What the adjectives rarely supply is a number. If the dealer deals 85 percent of the shoe instead of 50, how many more of your rounds actually begin at a true count worth noticing?
We answered that by rerunning the simulation behind our table of how often each true count comes up with exactly one change. Same engine, same rules, same counting method. Only the position of the cut card moved, from 50 to 85 percent of the six decks. The result is a clean picture of what penetration actually changes: how many rounds start at a count far from zero.
The setup, four identical runs
The original simulation dealt about 414 million blackjack rounds: one player against the dealer, a flat bet of one unit, basic strategy for the rules with no count-based plays. The setup was six decks, dealer stands on soft 17 and peeks, blackjack pays 3:2, double on any two cards, double after split, split to four hands, one card to split aces with no resplitting, no surrender. Before each round, the Hi-Lo running count was divided by the exact decks remaining, floored, and recorded, using the running count to true count conversion.
For this piece we held every one of those choices fixed and varied only where the cut card sits. The 75 percent column below is that original 414 million round run; the 50, 65 and 85 percent columns are fresh runs of about 15 million rounds each on the same engine. Counted as independent rounds, the standard error of any share in those 15 million round runs is at most 0.013 percentage points. Rounds from the same shoe share a count history, so the real uncertainty is a few times larger, still hundredths of a point and far smaller than any difference discussed below.
What the table says
Each cell is the share of rounds that started in that floored true count range, by cut card depth:
| True count at start of round | 50% | 65% | 75% | 85% |
|---|---|---|---|---|
| +1 or higher | 20.90% | 24.53% | 26.56% | 28.20% |
| +2 or higher | 8.79% | 12.51% | 14.79% | 17.11% |
| +3 or higher | 3.42% | 6.21% | 8.31% | 10.54% |
| +4 or higher | 1.23% | 3.02% | 4.64% | 6.63% |
| +5 or higher | 0.39% | 1.39% | 2.56% | 4.16% |
| +6 or higher | 0.11% | 0.61% | 1.37% | 2.63% |
| 0 (raw count 0 up to just under 1) | 32.80% | 28.85% | 26.62% | 24.86% |
| -1, 0 and +1 together | 68.85% | 61.70% | 57.35% | 53.39% |
| -2 or lower | 22.36% | 25.79% | 27.86% | 29.50% |
| -3 or lower | 9.40% | 13.07% | 15.44% | 17.77% |
Start at the top and the climb looks gentle: +1 or higher moves from 20.90 percent of rounds at 50 percent penetration to 28.20 at 85. Further from zero, the climb turns into a multiplier. Going from 50 to 85 percent penetration:
- +2 or higher grows from 8.79 to 17.11 percent, about 1.9 times the share (17.11 / 8.79 = 1.95).
- +3 or higher grows from 3.42 to 10.54, about 3.1 times (10.54 / 3.42 = 3.08).
- +4 or higher grows from 1.23 to 6.63, about 5.4 times (6.63 / 1.23 = 5.39).
- +5 or higher grows from 0.39 to 4.16, about 10.7 times (4.16 / 0.39 = 10.67).
The further from zero, the more depth matters. A round starting at +5 or higher is roughly a one in 256 event at 50 percent penetration (100 / 0.39 = 256) and about one in 24 at 85 (100 / 4.16 = 24). The middle of the distribution thins out: the -1, 0 and +1 rows together hold 68.85 percent of rounds at the shallow cut and 53.39 at the deep one.
The negative side grows the same way. Rounds at -3 or lower rise from 9.40 to 17.77 percent, about 1.9 times the share (17.77 / 9.40 = 1.89), and -2 or lower from 22.36 to 29.50. Depth does not pick a side; it widens the whole distribution, most at the extremes.
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Why the deep end owns the tails
No exotic mechanism is needed. The true count is the running count divided by the decks remaining, and both halves of that fraction change as the shoe is dealt. Our piece on how the count moves through a shoe measured the spread at fixed depths across 200,000 shoes: the true count's standard deviation grows from 1.16 after one deck dealt to 2.59 after three and 4.48 after 4.5, because the running count's spread rises until the halfway point and narrows only modestly after it, while the decks it is divided by keep shrinking.
A cut card at 50 percent ends each shoe after about 3 decks. The rounds where the true count has spread widest never get dealt; the shuffle cancels them. Moving the cut card deeper does not make any individual round richer. It removes the shuffle that was cutting the widest part of the shoe off. Our penetration explainer makes the point in one line: penetration does not make favorable moments more favorable so much as it makes them happen at all. The table puts numbers on that sentence.
Deeper cuts also deal more rounds
Depth changes a second thing at the same time: how many rounds each shoe produces. Six decks hold 312 cards, and per our piece on how many cards a blackjack hand uses, a heads up round consumes about 5.48 cards. Divide the cards in front of the cut card by 5.48 and you get about 28.5 rounds per shoe at 50 percent penetration (156 / 5.48), 37.0 at 65 percent (202.8 / 5.48), 42.7 at 75 (234 / 5.48) and 48.4 at 85 (265.2 / 5.48). The real figures run slightly higher, because the round in progress when the cut card appears is always finished: that piece's simulation at 75 percent produced 43.1.
Where those extra rounds sit is the whole story. Deal the same shuffled shoe to two different cut card positions and the deeper game deals every round the shallower one does, then keeps going. Everything it adds begins past the shallower cut card, 3 decks in when that card sits at 50 percent, where the count has had room to spread. So depth adds rounds, and the rounds it adds are disproportionately the wide-count kind. The two effects are one: the shares in the table shift because every added round comes from the deep end.
The flat bettor notices nothing
All four runs kept the same flat one unit bet and the same fixed chart, a control group for whether depth by itself helps someone who ignores the count. Nothing in the results says it does. The runs returned -0.47 percent of the initial bet at 50 percent penetration, -0.48 at 65, -0.43 at 75 and -0.40 at 85, and the three 15 million round runs each carry a standard error of about 0.03, so the gaps between those four numbers are within the noise. There is no signal in this data that rewards seeking a deep game while playing a fixed chart.
That is the same conclusion our piece on whether penetration matters without counting reaches from the published analysis. Per hand, the cut card changes almost nothing for a basic strategy player, and the one measurable effect, the cut card effect, is a small cost, about two hundredths of a percent at six decks per Wizard of Odds. Depth matters only to someone who acts on the count. For everyone else, a deeper shoe mostly means fewer shuffles per hour.
How to hold these numbers
Keep the qualifiers attached. These shares are for six decks, one player against the dealer and Hi-Lo; a fuller table, a different game or another counting system can move them. And this table says how often counts appear, not what any count is worth; it is a frequency result, not bet sizing or playing advice.
The standing cautions apply. Counting with your head is legal in the United States, but casinos are private businesses that may refuse service to suspected counters, and no technique removes the risk from the game; our pieces on whether card counting is illegal and on when counting is not worth the effort cover the legal side and the practical limits.
If you want to train the skill this table frames, 21 Trainer's rule customization includes penetration and shuffler settings alongside deck count and the other rules, and the Pro upgrade includes a true count drill for the conversion itself, with virtual chips and nothing at stake.
Frequently asked questions
Does deeper penetration make high true counts happen more often?
Yes. In our six deck simulation the share of rounds starting at a floored true count of +2 or higher rose from 8.79 percent at 50 percent penetration to 17.11 percent at 85 percent, and at +5 or higher from 0.39 to 4.16 percent. The further the count is from zero, the more the cut card position matters.
Why does the true count spread more late in the shoe?
Because the true count divides the running count by the decks remaining. Late in the shoe the running count's spread has narrowed only modestly while the denominator has shrunk a lot, so the same running counts convert to much bigger true counts. A cut card placed shallow ends the shoe before most of that spreading has happened.
Does penetration matter if you do not count cards?
Almost nothing, per hand. In the simulation, the flat betting player following a fixed chart lost between 0.40 and 0.48 percent of the initial bet at every depth, differences within the statistical noise. The one measurable effect of a cut card on a basic strategy player is a small cost, about two hundredths of a percent at six decks, per Wizard of Odds.
How many more hands do you get from deeper penetration?
Six decks hold 312 cards, and a heads up round uses about 5.48 cards, so dividing the cards before the cut card by 5.48 gives roughly 28.5 rounds per shoe at 50 percent penetration, 37.0 at 65 percent, 42.7 at 75 and 48.4 at 85, and slightly more once the round in progress at the cut card is finished. All of the added rounds come from the deep end, where the count has spread widest.
Is card counting illegal?
Counting with your head is legal in the United States. Casinos are private businesses that may refuse service to suspected counters, with some jurisdictional differences, and using an electronic device to count is a separate matter, prohibited in some jurisdictions. No technique removes the risk from the game.