# Spider suits: why a legal build is not always a movable run In Spider you can put a 7♥ on an 8♠ and the game accepts it at once. Ten moves later, that placement may be the reason a column will not open. Two-suit and four-suit Spider are mostly about the gap between what you may build and what you may move. ## Two rules that pull apart - Any card may be placed on a card one rank higher, regardless of suit. Any 7 goes on any 8. - A run can be moved together only if it is in descending order and all one suit. The first rule makes building easy; the second decides what you can do with the result. A stack such as 9♠ 8♥ 7♠ is perfectly legal, but it is three separate pieces: the 7♠ has to move on its own, then the 8♥, then the 9♠. In one-suit Spider the rules never clash, because every card is a spade. Two-suit Spider uses four sets each of spades and hearts and four-suit Spider uses two full decks, so there they clash all the time. All three modes use 104 cards. ## Count the pieces, not the cards A new piece starts wherever the suit changes or the rank does not drop by exactly one, and each piece needs its own landing place before the card underneath can be reached. Four-suit Spider, a column with two face-down cards under this stack (the last card listed is on top): ``` Column A: [2 down] 9♣ 8♦ 7♦ 6♠ 5♠ 4♥ ``` The six cards are in perfect descending order, yet they form four pieces: 9♣, then 8♦ 7♦, then 6♠ 5♠, then 4♥. Only the 4♥ can move now. To turn over the face-down card you need four separate homes: 1. 4♥ onto any 5. 2. 6♠ 5♠ onto any 7. 3. 8♦ 7♦ onto any 9. 4. 9♣ onto any 10. The table has to offer a 5, a 7, a 9 and a 10 on top of other columns, or empty columns to stand in for them. If the same six ranks were all clubs, 9♣ 8♣ 7♣ 6♣ 5♣ 4♣, the column would be a single piece that moves in one go onto any 10 or into an empty column. Six cards in one piece need one landing place; three cards in three pieces need three. ## Cards leave only as complete runs Spider has no foundation for single cards. A card leaves the table only as part of a complete same-suit run from King down to Ace, and those 13 cards are removed automatically as soon as the run is finished with the Ace on top. If a face-down card lay under the run, it then turns face up. So suit is the only way off the table: - Two-suit Spider needs four spade runs and four heart runs. - Four-suit Spider needs two runs in each of the four suits. - A column reading K♥ Q♠ J♥ and on down to A♥ is not removed, however tidy it looks. Only the J♥ to A♥ part, 11 cards, can move as a unit; the K♥ and the Q♠ are separate pieces. Every off-suit placement is a small debt: sooner or later those cards must be pulled apart and rebuilt in suit. ## When an off-suit build is still right Building in suit is the default, not an absolute rule. An off-suit placement is worth it when: - It turns over a face-down card, which usually matters more than tidiness, especially early on. - It empties a column, the best sorting tool in the game; see [why an empty column is so valuable](spider-empty-columns.html). - It frees a card you need for a same-suit join elsewhere. It is a poor move when it covers a same-suit run you were about to extend, or only shifts face-up cards around without revealing anything. When a card has two legal homes and one of them is its own suit, take that one. ## Repairing a mixed build Off-suit builds can often be repaired later, even without an empty column. Two-suit Spider: ``` Column A: [1 down] 8♠ 7♥ Column B: [1 down] 9♥ 8♥ Column C: [1 down] 10♠ 9♠ ``` The 7♥ went onto the 8♠ earlier because nothing better was available. Now column B shows an 8♥: 1. Move 7♥ from A onto 8♥ in B. Column B now ends 9♥ 8♥ 7♥, one movable heart run. 2. Move 8♠ from A onto 9♠ in C. Column C now ends 10♠ 9♠ 8♠, one movable spade run, and column A's face-down card turns over. Two moves turned a mixed column into two clean runs and revealed a card. When the top card of a mixed stack gets a same-suit home, moving it often repairs two columns at once. ## Try it Two-suit Spider. A column holds two face-down cards with this stack on top: ``` [2 down] 10♥ 9♠ 8♠ 7♥ 6♥ 5♠ ``` 1. How many pieces does the stack contain? 2. Which cards can move right now? 3. Another column shows a 6♠. Where should the 5♠ go, and what does that free? **Answers:** Four pieces: 10♥, then 9♠ 8♠, then 7♥ 6♥, then 5♠. Only the 5♠ can move, because the suit changes between the 6♥ and the 5♠. Put it on the 6♠: that is a same-suit join, and the 7♥ 6♥ pair left on top can now move as a unit onto any 8. Practise on [Spider two suits](../play/spider-two-suits.html) or [Spider four suits](../play/spider-four-suits.html), and compare the levels in [one, two or four suits](spider-one-two-four-suits.html).