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Blackjack table

Blackjack · 20 rounds · Sep 25, 2026, 8:38 PM UTC

Round 20

Dealer

Round 20 result · Dealer 20

Claude Opus 5.5 Loss -10
1

Claude Opus 5.5

1,020

 

Hand 1 · 14 · bet 10

Loss -10

207 / 207

Action timeline

Model's stated reason

Hard 20 against a dealer 10 is a strong standing hand, and basic strategy never splits tens. Splitting or hitting would throw away a high win probability.

Model's stated reason

A hard 5 against a dealer 8 can't bust with one more card, so basic strategy says hit. Doubling here is a clear mistake.

Model's stated reason

Hard 14 against a dealer 8 is a hit under basic strategy, since the dealer's 8 is strong and standing on 14 loses more often.

Model's stated reason

Basic strategy says to double a hard 11 against a dealer 7 in a 6-deck S17 game, since doubling has the highest expected value here.

Model's stated reason

Basic strategy says to stand on a hard 17 against any dealer upcard. Against a 7, a hit busts too often to be worth it.

Model's stated reason

Hard 16 against a dealer 7 is a hit under basic strategy. The dealer is likely to make 17 or better, so standing loses more often.

Model's stated reason

Hard 18 against a dealer 7 is a clear stand under basic strategy. Hitting risks busting, while standing is favored against a dealer likely to make 17.

Model's stated reason

Basic strategy says to stand on hard 12 against a dealer 4, because the dealer has a high chance of busting.

Model's stated reason

Hard 12 against a dealer 10 is a hit under basic strategy. Standing loses more often because the dealer's strong upcard is likely to finish on 17 or higher.

Model's stated reason

A hard 13 against a dealer 10 is a hit under basic strategy, since the dealer is likely to make 17 or better.

Model's stated reason

Hard 15 against a dealer Ace (S17, no surrender) is a basic-strategy hit. Standing loses more often than drawing.

Model's stated reason

Hard 18 against a dealer Ace should stand under basic strategy (S17, dealer peeks), since hitting risks busting more than it gains.

Model's stated reason

Basic strategy says to hit a pair of 2s against a dealer 10; splitting against a strong upcard loses value. A total of 4 can't bust, so hitting is clearly better than standing.

Model's stated reason

Basic strategy says to hit a hard 14 against a dealer 10 when surrender isn't available. Standing on 14 loses more often than hitting.

Model's stated reason

Basic strategy for soft 18 (A,7) against a dealer 4 in a 6-deck S17 game is to double. The dealer's weak upcard makes the extra bet profitable.

Model's stated reason

A hard 20 against a dealer 10 is a strong favorite, and basic strategy says to stand rather than split tens.

Model's stated reason

Basic strategy for a 6-deck S17 game says to stand on hard 16 against a dealer 2, since the dealer's bust chance outweighs the risk of hitting.

Model's stated reason

A hard 7 against a dealer 10 is a clear hit under basic strategy. No card can bust the hand, and doubling on 7 is never correct.

Model's stated reason

Hard 13 against a dealer 10 is a hit under basic strategy, because standing loses more often than risking a bust.

Model's stated reason

Hard 14 against a dealer 10 is a hit in basic strategy, even with multiple cards. Standing on 14 loses too often to a strong dealer upcard.

Model's stated reason

Basic strategy says hit a hard 7 against a dealer 6. Doubling with 7 is not favorable, and the hand can't bust on one card.

Model's stated reason

A hard 11 cannot bust on the next card, so hitting is clearly better than standing. Doubling isn't allowed with three cards.

Model's stated reason

A hard 20 against a dealer 3 is a strong standing hand. Splitting tens gives up a large expected win, so basic strategy says stand.

Model's stated reason

Basic strategy says to hit a hard 15 against a dealer 10, since surrender isn't available. Standing on 15 against a 10 loses more often than hitting does.

Model's stated reason

Hard 19 against a dealer 7 is a clear stand under basic strategy. Hitting or doubling would only risk busting a strong hand.

Model's stated reason

Under basic strategy a hard 14 stands against a dealer 4, because the dealer's weak upcard gives a high chance the dealer busts.

Stated reasons appear after the comparison block is revealed. They are model-submitted text, not verified reasoning.

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Result

Session result: +20 chips over 20 rounds

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