Chükö

Caravan

A solitaire game for one pack of 12 Chükö cards. Build a single caravan by connecting cards that share a prime factor. You may play up to two of your cards face down as bridges. Use all 12 cards to win.

Setup

Shuffle the 12 playing cards and deal them face up in three rows of four (4 × 3). Keep every card visible and leave room nearby for your caravan.

A  B  C  D
E  F  G  H
I  J  K  L

Only the leftmost remaining card in each row is available. In this layout, your first choices are A, E, and I. Whenever you take a card, the next card in that row becomes available. Keep the remaining cards in order.

Play

Choose any available card and place it face up in the play area to start your caravan. The first card is free.
Take an available card and add it face up to either the left or right end of the caravan. When the card at that end is face up, the two cards must share at least one prime factor. For example, 6 and 15 connect because both have a factor of 3; 14 and 8 connect because both have a factor of 2.
Instead, you may take an available card and place it face down beside a face-up card at either end. This uses that card as a bridge; its number no longer matters. You may do this even when a face-up move is available, but you may use no more than two bridges in the whole game.
The next card added at a bridge end must be face up and may be any available card, regardless of its factors. This completes the bridge between two face-up cards. You may play at the other end while a bridge is unfinished, but you may not place two bridges next to each other.
Continue taking cards from the rows and adding them to either end. Cards already in the caravan stay in place and cannot be turned over or reused.

Winning

You win when all 12 cards are in the caravan, counting both face-up cards and face-down bridges, and every bridge is between two face-up cards. Both ends must be face up, but they do not need to match each other.

If cards remain but you cannot make a legal move, or you use all the cards with a bridge still unfinished, the game is over without a win. Some deals cannot be won.

Example

Suppose your caravan starts with 11 and one row begins with 6, 15, 10. You may take the 6 and place it face down beside 11 as a bridge. This exposes 15, which you can place face up beyond the bridge without matching 11. The 10 is now available and can connect to 15 because both share a factor of 5:

11 — [6 face down] — 15 — 10

You have played four of your 12 cards and used one bridge. You may turn one more available card into a bridge. A face-up move must now match 11 or 10.

Difficulty

Use up to two bridges for the standard game. For learning or a more forgiving game, allow up to three. For a harder game, allow only one.

Strategy

Look ahead along each row before choosing a card: a move changes both an end of the caravan and which card becomes available next. Cards with several different prime factors can connect different parts of your pack. Consider using a card with few connections as a bridge, especially when it exposes a useful card behind it. Do not wait until you are stuck to consider a bridge, and leave enough cards to complete any unfinished bridges. All cards start face up, so take your time and plan ahead.