Blackjack played with a 48-card deck, the tens removed.
In exchange for 10-point cards being a quarter of the deck (J, Q and K stay), a player 21 always wins, and you can double on any number of cards, rescue after a double, resplit aces and surrender. Bonuses (not on doubled hands): 21 with 5 cards pays 3 to 2, 6 cards 2 to 1, 7 or more 3 to 1, and 6-7-8 or 7-7-7 pays 3 to 2 to 3 to 1. Example: a 6-card 21 on a 10 bet pays 20. With 6 decks and S17 the house edge is about 0.4%, and the strategy depends on the number of cards.