Only kings can plug an empty column here, unlike Citadel's anything-goes rule, so brace for one of the site's toughest single-deck games at 4%.

Exiled Kings Solitaire takes Citadel and removes its safety net: only kings can fill an empty tableau column, instead of any card. That one change turns a fairly forgiving Beleaguered Castle variant into one of the toughest games on the site, with just a 4% chance of winning. It's played with a single deck, and your result comes down to skill and a bit of luck in the deal.
Other solitaire games like Citadel Solitaire and Beleaguered Castle Solitaire are close relatives.
If you enjoy Exiled Kings, Solitaire is the traditional version worth a look too.
If you run into anything odd or have an idea that would make the game better, please contact me.
Have a good time playing!
4 foundation piles: Build up from ace to king in the same suit. The four aces are dealt on these piles at the start of the game.
8 tableau piles: Build down in any suit. Only the top card of each pile is playable. Only kings can fill empty spaces. Each pile gets 6 cards at the start of the game, and any card that can go straight to a foundation is moved there as it's dealt.
There are four foundation piles.
Each foundation pile starts with an ace.
A card can be added to a foundation pile if it's one rank higher than the pile's current top card and the same suit. So the only card that fits on a 4 of diamonds is the 5 of diamonds.
A foundation pile's top card can move back into play if another pile will accept it.
Eight tableau piles of six cards each, all dealt face-up.
Any card that can go straight to a foundation during the deal is sent there immediately.
A card can be added to a tableau pile if it's one rank lower than the pile's current top card, of any suit. So the only cards that fit on a jack are the four tens.
Any tableau card not covered by another card is free to move to a foundation or another tableau pile.
Only kings can fill an empty tableau space.
You can only move one card at a time; sequences aren't allowed.