The main difference between "Christmas Solitaire" online games and regular solitaire games is the Christmas theme of the cards, which often include Santa Claus, Christmas trees and holly. The rules of the game remain the same, with a focus on completing four stacks of numerical ascending suits.
Several sites, such as Christmas-Solitaire.com and ChristmasSolitaire.com, feature Christmas versions of standard solitaire games as a means of incorporating a holiday theme into the classic game. Many sites simply use a Christmas deck of cards that features different iconography on the faces and backs of the cards, though some also add Christmas themes to the site itself. In all cases, the game follows the same rules of play, depending on the variation of solitaire used.
The standard rules of solitaire dictate that the player must rearrange the cards in play in order to fill four foundations at the top of the field. The player must place an ace in each of the four suits into a foundation when it is available, then continue to place the next card within the same suit on top. For example, if the player places the ace of spades on a foundation, she must next place the two of spades. She may move cards in the playing field in descending order on an alternate color to reveal new cards.