See all fifty-two cards from the first move: ten columns, no stock, no hidden cards. The only tool you get is an empty column, so guard it well.

Somerset Solitaire — sometimes catalogued under the name Usk — is one of the purest open builders in the solitaire canon. All fifty-two cards are dealt face-up across ten columns from the very first move, so nothing is hidden and there is no stock to draw from. What you see at the deal is the whole puzzle, which makes Somerset a game of planning far more than luck.
The triangular deal gives the game its distinctive shape. The first seven columns grow from a single card up to seven, while the last three columns each carry eight. Because there is no reserve and no redeal, the only working space you ever get is an empty column, and empties are precious: earning one and then deciding what deserves to sit there is the heart of the strategy.
Somerset sits at the head of a small family of related patiences. Morehead Solitaire keeps the identical layout but relaxes the tableau so you can build on any card of a different suit instead of alternating colors, while King Albert Solitaire and Raglan add reserve cards to soften the challenge. Learning Somerset first gives you the footing to enjoy all of them. Read the whole board before touching a card, free your aces and low cards early, and resist filling an empty column until you know exactly which card it will unlock.
The original Solitaire is still there whenever you want the standard rules back.
If you run into anything odd or have an idea that would make the game better, please contact me.
Have fun playing!
4 foundation piles: Build up in suit from Ace to King. Cards move here automatically when they are ready.
10 tableau piles: Alternate color build down, one card at a time. Any card can fill an empty column. At the start, the first seven piles are dealt one through seven cards and the last three piles eight cards each, all face-up.
There are four foundation piles, each starting empty.
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 the 6 of clubs is the 7 of clubs. Each pile is complete once it runs from Ace up to King.
The top card of each foundation can be moved back into play if another pile will accept it.
Ten tableau piles, every card dealt face-up. The first seven piles hold one through seven cards and the final three hold eight cards each.
A card can be added to a tableau pile only if it's one rank lower and the opposite color of the pile's current top card, so the only cards that fit on the 8 of spades are the 7 of hearts and the 7 of diamonds.
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 card can fill an empty slot in the tableau.
Only one card may be moved at a time; sequences are not permitted.