Fortress

Fortress belongs to the Castle family — the group that includes Beleaguered Castle and Streets and Alleys — and it is the one with the most rows and the shortest of them: ten in all, arranged either side of a central space where the foundations go.

Its distinguishing rule is pleasant and rare: the tableau builds up or down by suit, whichever you prefer, so a card has two possible homes rather than one. That flexibility is welcome because everything else is tight — single-card moves, no round-the-corner building, no redeal. The article notes plainly that the odds are slim, and the culprit is how the high cards fall across ten short rows.

Ten rows sit either side of a central space reserved for foundations — two rows of six and eight of five, all face up. The tableau builds either up or down by suit, whichever suits you, but strictly one card at a time and never round the corner: an Ace will not go onto a King. Aces are dug out of the rows to found the centre and build up by suit to King. Any available card may fill an emptied row, and there is no redeal at all.

Being able to build both up and down by suit is unusually flexible and is the main tool you have, since one-card moves and no redeal give you nothing else. Use it to park cards temporarily in the direction you do not need, rather than committing them to a foundation you might still want to build through. Empty rows take any card, so unlike its Castle-family relatives an emptied row is genuinely useful here — worth working for. The article is blunt that odds are slim, and the reason is the distribution of high cards across ten short rows: identify which Kings are sitting on top of cards you need early, because they are what strands most deals.