Blackjack table

Hard 11 is the strongest double in basic strategy, including against a dealer 10, because one card often makes 21 and the extra bet has positive expectation.

I have a hard 20 against a dealer 10, which is a strong made hand. Standing is clearly best; hitting, doubling, or splitting tens would only risk a winning hand.

Hard 19 against a dealer ace is a clear stand; hitting or doubling risks a strong made hand.

Hard 15 against a dealer 2 is a basic-strategy stand: the dealer is weak and hitting risks busting a made total.

Pair of nines against a dealer 2 is a standard split: each nine starts a strong hand versus a weak upcard, and standing on 18 is inferior.

Soft 20 is already a strong total against a dealer 2, so standing avoids risking a worse total by taking another card.

Hard 12 against a dealer 2 should be hit under basic strategy; standing is only correct versus 4–6, and doubling is not advantageous here.

Hard 15 against a dealer 2 is a basic-strategy stand; the dealer is weak and hitting risks busting a playable total.

Hard 17 against an Ace is a clear stand; hitting risks busting and doubling is worse.

Hard 17 versus a dealer 6 is a stand: hitting busts on most cards, and doubling a stiff 17 has negative expectation.

A hard 20 is already a strong made hand against an Ace, and splitting tens or taking another card would only worsen the expected value.

Hard 12 versus a dealer 7 is a hit under basic strategy; standing loses too often to the dealer's made hands, and doubling is negative EV.

Hard 14 versus a dealer 7 is a hit under basic strategy; standing would lose too often to the dealer's likely made hand.

Hard 16 versus a dealer 7 is a hit under basic strategy; standing loses too often when the dealer makes a hand.

Hard 12 versus a dealer 7 should be hit under basic strategy; standing loses too often and doubling a stiff total is negative EV.

Hard 20 against a dealer 7 is a strong made hand; hitting risks busting and standing is the clear basic-strategy play.

Soft 14 versus a dealer 10 is a hit in basic strategy; doubling is too weak and standing leaves a poor total.

Soft 20 is a strong total against a dealer King; hitting risks a worse hand, so standing is correct.

Hard 13 against a dealer 9 is a hit in basic strategy; standing loses too often to a made dealer hand and doubling is too risky.

Hard 12 versus a dealer 7 is a hit under basic strategy; standing loses too often to the dealer's made hands, and doubling is not justified.

Hard 17 versus a dealer 7 is a stand under basic strategy; hitting risks busting a made hand.

Hard 16 versus a dealer 10 is a hit in basic strategy; standing loses to most dealer totals and doubling is too risky.

A pair of fives is played as hard 10, not split. Against a dealer 5, basic strategy doubles hard 10.

Pair of aces should always be split; against a dealer 5 this is the highest-EV basic-strategy play.

Hard 16 versus a dealer 3 is a basic-strategy stand: the dealer is weak and hitting risks busting a made hand. Doubling is not justified with this total.