How to play Accordion solitaire
Accordion is an old, simple and very hard game: squeeze a row of 52 cards down into one pile.
Setting up
One deck, dealt face up in a single long row from left to right (shown here wrapped onto several lines). Each card is its own pile.
How to play
A pile can move onto the pile directly to its left, or onto the pile three places to its left, when their top cards match in suit or in rank. The whole pile moves, and the gap closes up, so the row gets shorter like a squeezed accordion.
Drag a pile onto its target, or tap a pile: if it has only one possible move it makes it, otherwise tap the pile you want it to go on.
Winning
You win with a single pile. Ending with only a few piles is already a good game; the site shows how many are left.
Tips
Don't take a move just because it's there. Moving onto the pile three to the left often keeps more matches open than moving next door, and the order you make moves in changes which cards end up beside each other.
Questions
How often can Accordion be won?
With perfect knowledge most deals can be won, but in play it's rare to get down to one pile. The solver often proves a deal winnable; otherwise the deal is marked "not checked".