Others say it originated in Spain through a game called One-and-Thirty, which translates to 31. Some say it was from the Romans, who played a similar game with wooden blocks. There is an ongoing debate about the exact precisions of its origins. What is blackjack? It is a popular card game in casinos today, both online and brick and mortar casinos. Fans of unearthing mysteries will appreciate everything there is to know about blackjack.