Beleaguered Fortress crosses Fortress with Beleaguered Castle: an eight-pile wall backed by a twelve-card reserve where every card plays, but never refills.

As its name suggests, Beleaguered Fortress Solitaire marries two of the oldest open patiences: it takes its walls from Fortress Solitaire, a game built in the 1870s, and its name from Beleaguered Castle Solitaire. Like Fortress, the tableau may be built both up and down in the same suit — but here the wall is only forty cards strong, eight piles of five, and the twelve cards left over are spread beneath it as a reserve.
That reserve is what sets the game apart. Every one of the twelve cards is available at any moment — not just the one on top — yet the reserve is never replenished, so each card is a one-shot resource. Spent well, a reserve card pries open a stalled column or opens a foundation; spent carelessly, it is simply gone, and the wall closes ranks behind it.
Roughly 15% of games end in a win, which is enough to call it difficult; play a single deck with every card visible from the first move, and the result rides mostly on how well you read the reserve.
Want the classic instead? Head to original Solitaire any time.
If you run into anything odd or have an idea that would make the game better, please contact me.
Enjoy playing!
4 foundation piles: Build up in suit from Ace to King. All four piles start empty.
8 tableau piles: Build up or down in the same suit. Five cards are dealt face-up to each pile, and any card may fill an empty space.
Reserve: 12 cards spread face-up in two rows below the tableau. Every reserve card is available for play at any time.
There is no stock and no waste; the whole deck is on the table from the very first move.
There are four foundation piles, and they begin the game empty.
Any Ace may be moved to an empty foundation pile. A card can be added to a foundation pile only if it's one rank higher and the same suit as the pile's current top card, so the only card that fits on an 8 of spades is the 9 of spades. There can be no more than 13 cards in a pile.
The top card of each foundation can be moved back into play if another pile will accept it.
There are twelve reserve cards, dealt face-up in two rows of six. Unlike most reserves, every card is available at all times — not just the one on top.
A reserve card may be played to the foundations, built onto a tableau pile, or moved into an empty tableau spot. No card may ever be moved into the reserve, and an emptied slot stays empty for the rest of the game.
Eight tableau piles of five cards each. Every card is dealt face-up.
A card can be added to a tableau pile only if it's one rank higher or one rank lower and the same suit as the pile's current top card, so the only cards that fit on an 8 of spades are the 7 of spades and the 9 of spades.
Cards on the tableau that are not covered by another card are free to be played onto the foundation or any other tableau pile.
Any single card — whether from the tableau or the reserve — may fill an empty tableau spot.
Only one card may be moved at a time; sequences are not permitted.