What is Forty Thieves solitaire?

Forty Thieves uses two decks, 104 cards, dealt into ten tableau columns of four. You build the eight foundations up in suit from Ace to King and the tableau down in suit, moving just one card at a time by strict rules. The name comes from the forty cards in the opening tableau layout.

Two things make it brutal: builds must follow suit, not just color, so landing spots are scarce, and you get only one pass through the stock with no redeals. Every card you skip is gone for good, so a single buried card at the wrong moment can end the game. That's why it sits among the hardest solitaire games.

Forty Thieves is often linked to Napoleon, who supposedly played patience during his exile on St Helena, hence the alternate name Napoleon at St Helena. Whether or not the story is true, the game's difficulty fits the image. If you want a two-deck challenge without Spider's same-suit runs, this is the classic choice, and it uses two full decks like Spider.