Hole Carding

Hole carding in Blackjack refers to using knowledge of the dealer downcard. How that information is obtained will not be discussed here. Theoretically the gain can be enormous with a SCORE over 10,000. However, the practical gain is limited because:

We will not see every downcard
We cannot always play ideally. For example, if the dealer has 20 and you have 19 you cannot win without hitting. But hitting will draw enormous attention.
Always betting Insurance correctly will also draw attention.
Sometimes we will only obtain partial information. For example, the card has or has not pips near the edge or corner.

Six Deck Hole Carding Strategy

Below is an ideal strategy for six decks, S17, DAS. The advantage is 12.95% if you always win Insurance and about 10.6% if you never take Insurance. (The normal Basic Strategy advantage for this game is -0.43%)

Hard Hit/Stand

(Hit on green, Stand on red)

Soft Hit/Hand

(Hit on green, Stand on red)

Hard Double Down

(Double on green)

Soft Double Down

(Double on green)

Split

(Split on green)

Single Deck Hole Carding Strategy

Below is an ideal strategy for single deck, H17, nDAS. The advantage is 12.5% if you always win Insurance and about 10.1% if you never take Insurance.

Hard Hit/Stand

(Hit on green, Stand on red)

Soft Hit/Hand

(Hit on green, Stand on red)

Hard Double Down

(Double on green)

Soft Double Down

(Double on green)

Split

(Split on green)

Compromise Strategy

Below is a six deck sample compromise strategy designed to make it less obvious that you are hole-carding. The advantage is 9.6% if you always win Insurance and 7.2% if you never take Insurance. However, a full compromise strategy would require two sets of tables - one for a high dealer upcard and one for a low dealer upcard.