Klondike Solitaire

Klondike is the single-player card game most people mean when they say 'solitaire'. Seven tableau columns of increasing length are dealt from a shuffled deck; play builds foundations up by suit from Ace to King, and tableau piles down in alternating colours. Popularised worldwide as Microsoft's default Windows Solitaire from 1990. Only about 82% of games are winnable with perfect play.