Seven columns of cards, most of them face down. You build downward in alternating colours to dig out the buried ones, and you send aces up to four foundation piles that you fill from ace to king. Get all 52 up there and you have won.
This is the solitaire that shipped with every computer for about twenty years, so it's probably the version you already have in your head.
The columns get dealt at increasing lengths, one card up to seven, and only the bottom card of each is face up. Everything else is hidden.
Almost every move you make should be aimed at flipping one of those face down cards over. A move that just shuffles face up cards around usually accomplishes nothing. When you've got a choice between two moves that look the same, take the one from the longer column, because it has more buried cards underneath.
This is the mistake that loses the most games. Sending a card up to the foundation feels like progress, but a card up there is out of play. If you send the four of diamonds up and then turn over a black three, there's nothing to put it on.
Hold your low cards in the tableau until you're sure nothing needs them. Late in the game, once you can see everything, send it all up.
An empty column can only be filled by a king, which makes it more valuable than it looks and also means you shouldn't waste it. Once a king goes in there it's stuck. Think about which king you actually want in that space before you fill it.
Draw one turns the stock over one card at a time and you can reach everything. Most deals go out. Draw three only lets you reach every third card unless you change the alignment, and the win rate drops a lot.
Both are here and you can switch mid game.
Worth saying because it's the most common frustration with this game. A real chunk of Klondike deals are impossible no matter how well you play them. If a deal beats you, replay it and find out whether it was ever winnable.
The full guide to Klondike has the rules and the priorities that raise your win rate.
Klondike is named after the Yukon gold rush and is far and away the best known solitaire. Most people who say "solitaire" mean this, largely because a version of it came bundled with every copy of Windows from 1990 onwards.
This version is written from scratch to run in a browser. There's no download and no account, it works on a phone as well as a desktop, and empty seats are filled by bots so a game starts the moment you want one. The full rules, scoring and strategy are on the Klondike rules page.
Can every deal be won?
No. A real proportion of Klondike deals are impossible however well you play.
What's the difference between draw one and draw three?
Draw one lets you reach every card in the stock. Draw three only lets you reach every third card unless you change the alignment.
Can I take a card back off a foundation?
Not in this version, which is why holding low cards back matters.
What goes in an empty column?
Only a king.
If something here is broken, or a rule doesn't match the way you play, email hello@turngames.io. Saying which game and what you were doing helps. Requests for new games are welcome too.