Blackjack · 20 rounds · Sep 25, 2026, 8:38 PM UTC
Round 20
Dealer
Round 20 result · Dealer 20
Claude Opus 5.5
Hand 1 · 20 · bet 10
Push
Hard 11 against a dealer 7 is a standard double in basic strategy. It is strongly +EV to double here.
Basic strategy says to hit a hard 13 against a dealer 8, because standing on 13 loses more often than risking a bust.
A hard 7 against a dealer 8 cannot bust on the next card, and basic strategy says to hit. Doubling here has lower expected value than simply hitting.
A hard 11 can't bust on a hit and is a strong total to draw to, and doubling isn't allowed with three cards. Hitting against the dealer's 8 is clearly correct.
Basic strategy for a 6-deck S17 game is to double a hard 9 against dealer 3-6, and the dealer's 4 is a weak upcard.
Hard 18 against a dealer 10 is a stand under basic strategy. Hitting or doubling risks busting on most cards.
A hard 20 against a dealer King is a strong made hand, and basic strategy says stand. Splitting tens gives up a likely win for two weaker starting hands.
Hard 11 against a dealer 7 is a standard double down under basic strategy, since the expected value is highest when doubling.
Basic strategy says always split aces. Each ace starting a new hand is far stronger than a soft 12 against a dealer 8.
Soft 15 against a dealer 10 is a clear hit in basic strategy. Doubling is wrong against a strong upcard, and standing on 15 is too weak.
Soft 20 against a dealer 10 is a clear stand under basic strategy. Hitting cannot improve the hand's expectation.
Hard 12 against a dealer 7 is a hit in basic strategy. The dealer's strong upcard makes standing worse than taking a card.
A hard 20 is a strong hand even against a dealer Ace, since the dealer has already peeked and has no blackjack. Splitting tens gives up that edge, so basic strategy says stand.
Basic strategy says to double a hard 10 against a dealer 4, because the dealer's weak upcard makes it busts often while we are likely to draw a strong total.
Hard 11 against a dealer 6 is a textbook double: the dealer is in a weak bust position and we have a strong chance of drawing to 20 or 21.
Basic strategy for a 6-deck S17 game says to double hard 11 against a dealer 9, since this is a strongly favorable spot.
A hard 18 against a dealer 4 is a clear stand in basic strategy. The dealer's weak upcard gives a good chance they bust, while hitting or doubling would risk busting my own strong hand.
Hard 20 against a dealer 10 is a strong standing hand, and basic strategy never splits tens. Standing keeps the high expected value.
Hard 20 against a dealer 10 is a strong standing hand. Splitting tens gives up a likely win, so basic strategy says stand.
Hard 10 against a dealer 7 is a standard double under basic strategy for 6 decks with the dealer standing on soft 17. The player's edge is strong enough to justify doubling the bet.
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Session result: +100 chips over 20 rounds
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