Short answers, pulled from the story.
The popular myth claims gambling houses offered a ten-to-one payout if a player held the ace of spades and a black jack. French historian Thierry Depaulis found no historical evidence for this special bonus. He suggests prospectors during the Klondike Gold Rush from 1896 to 1899 named the game after zincblende mineral deposits often associated with gold.
Miguel de Cervantes wrote a story called Rinconete y Cortadillo between 1601 and 1602. Two card cheats in Seville play a game they call veintiuno, which means twenty-one. The protagonists state the goal is to reach 21 points without going over.
Roger Baldwin published The Optimum Strategy in Blackjack paper in September 1956 within the Journal of the American Statistical Association. Ed Thorp verified these calculations and later released Beat the Dealer book in 1963. Using basic strategy reduces long-term losses to less than 1% of total wagers.
Scraping cards against the table signals a request for another card in handheld games. Tapping the table with a finger or waving a hand toward the body works for face-up dealing. Sliding cards under chips face-down indicates standing pat in handheld formats.
Card counting systems assign point scores like one for cards two through six and minus one for tens through aces. Counters track running totals to determine when many high-value cards remain in the shoe. Insurance bets become advantageous when hole cards show greater than one-third chance of being ten-valued.