This interesting and unusual game was invented by programmer Randy Rasa, who kindly gave us permission to include Thirteens in Solitaire Till Dawn. If your non-Mac friends are jealous of Solitaire Till Dawn, tell them to look for Randy’s excellent shareware solitaire programs for Windows computers. His Web site, Solitaire Central, is at http://www.solitairecentral.com/. And if you like Thirteens, you should also try Mount Sunflower!
When a card is discarded, all cards above it in its column will “fall” down to fill the empty space. This in turn leaves an empty space at the top of the column, which is immediately filled from the stock. When the stock is empty, the spaces at the top of the column remain unfilled.
Towards the end of the game, one or two columns may become empty. You are then permitted to bring a card down from the top of another column to fill the single space at the bottom of each empty column. (This is an important rule. Without it, Thirteens becomes a much harder game to win.)
Match pairs in the middle column when you have a choice. Cards that fall down the middle column are adjacent to both side columns and have better chances of making future matches, so you want to slide lots of cards down that middle column.
When you can’t match in the middle, match side cards to middle cards. Only match sides to sides when there are no other good matches for those cards.
Make matches high in the columns first. If you play low matches first, the higher matches may drift apart and you’ll lose the opportunity.