Blackjack table

Hard 7 against a dealer 2 is best played as a hit. Basic strategy says doubling only starts at hard 9, and standing on 7 is too weak.

Hard 17 against a dealer 2 is a standard stand, since hitting risks busting with a high chance and gains little.

Hard 12 against a dealer ten is a basic strategy hit. Standing loses too often to the dealer's likely 17 or better, and doubling is not favorable.

Hard 13 (7+5+A counted as 1) against a dealer ten is a weak hand, and basic strategy says to hit hard 13 against a 10 because standing loses more often than hitting.

Pairs of 5s are played as a hard 10, but doubling against a dealer Ace is not recommended in basic strategy (dealer peeked, no blackjack; S17 6-deck: hit 10 vs A). Hitting is the better play than doubling here.

Hard 14 against a dealer Ace (strong upcard, dealer peeked and has no blackjack) is best played by hitting, since standing wins too rarely.

Hard 16 against a dealer 3 is a basic strategy stand, since the dealer has a high chance of busting and doubling 16 is not advisable.

Hard 20 against a dealer King is a strong made hand; standing is the basic strategy play, and splitting tens or doubling has lower expected value.

Hard 20 against a dealer 5 is a very strong hand. Splitting tens is worse than standing in basic strategy, so I stand.

Hard 18 against a dealer ten is a standard stand; hitting risks busting too often and doubling has negative expectation.

Hard 15 against a dealer 7 is a hit under basic strategy, since the dealer likely has 17 and standing on 15 loses more often than hitting. Doubling is not recommended on hard 15.

Hard 20 against a dealer 7 is a very strong hand, so standing is clearly correct. Hitting would almost certainly bust or make the hand worse.

Hard 5 against a dealer 9 is too weak to double under basic strategy, so hitting is the standard play.

Hard 12 against a dealer 9 is a basic strategy hit, since standing loses more often than the bust risk costs.

Hard 16 against a dealer 7 is best played by hitting under basic strategy. Standing loses more often in expectation, and doubling on 16 is not advisable.

Hard 19 against a dealer 3 is a clear stand; hitting risks busting and doubling has negative expected value.

A hard 20 against a dealer ten is a very strong hand; standing has the best expected value, and splitting tens is worse in basic strategy.

Hard 16 against a dealer 5 is a standard stand, since the dealer busts often with a weak upcard and hitting risks busting too much.

Hard 19 against a dealer 2 is a clear stand under basic strategy; hitting or doubling would add far more bust risk than expected gain.

Soft 19 against a dealer 9 is a stand in basic strategy; doubling only becomes correct against a 6 or lower, so standing is best here.

Hard 14 against a dealer ten is a basic-strategy hit. Standing loses more often than hitting, and doubling is not favorable here.

Hard 19 against a dealer ten is a clear stand; hitting would almost always make the hand worse.

Hard 19 against a dealer 4 is a clear stand; hitting or doubling would risk a strong made hand for no gain.

Hard 13 against a dealer 9 is a hit by basic strategy, since standing on 13 against a strong upcard loses more often. Doubling a 13 is not favorable.

Hard 19 against a dealer 3 is a strong made hand; basic strategy says stand, since hitting or doubling would risk busting or ruining a good total.