There's an ante from each player. Next five cards are dealt face down to each player; the undealt cards are laid in the center of the table to form the stock. The player to dealer's left draws the top card of the stock and discards, and thenceforth each player in turn has his choice between the top card of the stock and the top discard. The discard pile must be kept squared up and is not open for inspection.
Any player, in turn, after drawing and prior to discarding, may knock. This entails there will be a showdown when his turn comes again. The knocker then discards, and every player has one more turn where in he may draw like usual, and then he must either drop and pay the knocker a chip or discard and stay in the game.
When knocker's turn comes again, he doesn't draw— there's a showdown among all the players who stayed in. If the knocker bears the high hand, every player who stayed in pays him up two chips. If any other player ties the knocker, they split the winnings, except that the knocker keeps chips paid to him by players who dropped out. When anyone beats the knocker, he gets the antes, and the knocker pays two chips to each player who stayed in.
It's customary for bonuses to be paid (by each player, including those who might have dropped) as follows: two chips each for knocking on the beginning round and winning without drawing a card; one chip each for knocking prior to drawing on the first round, then drawing the top card of the stock and winning; four chips each for winning with a royal flush, two chips each for winning with any other straight flush, and one chip each for winning having four of a kind.