# Why is an empty column so valuable in Spider?

In Spider you will often have to choose between turning over one more face-down card and clearing a column completely. Why is an empty column usually the bigger prize, and what should you do with it once you have one?

## The rules that make it special

- Any card may be placed on a card one rank higher, whatever its suit.
- A run can be moved as one unit only if it is in descending order and all one suit.
- Any card, or any run that can be moved, may fill an empty column.
- Drawing from the stock deals one card onto each of the ten columns, and on Card Lounge you cannot draw while any column is empty.
- No card ranks above a King, so a King can never be placed on another card. The only place a King can move to is an empty column.

Put together, an empty column is the one spot on the table that accepts anything.

## Three jobs an empty column does

1. **Sorting suits.** Placing cards ignores suit, so mixed stacks build up quickly. An empty column gives you a spare place to rearrange them into same-suit runs, which can then move freely.
2. **Digging.** To reach a face-down card you have to move everything above it. An empty column can take a card or a same-suit run that has no other home.
3. **A base for a King.** A King, or a run headed by one, belongs in a column of its own: it is the start of a complete run from King to Ace, which is removed automatically once it is finished in one suit.

## Worked example: swapping two suits

Two-suit Spider uses spades and hearts. Suppose:

- Column A: 9♥ with 8♠ on top.
- Column B: 9♠ with 8♥ on top.
- Column C: empty.

Both stacks are legal, because any 8 may go on any 9, but neither is a run you can move as a unit. With the empty column it takes three moves to fix:

1. Move 8♠ from A into C.
2. Move 8♥ from B onto 9♥ in A.
3. Move 8♠ from C onto 9♠ in B.

Column A is now 9♥ 8♥ and column B is 9♠ 8♠. Both are movable runs, and column C is empty again, ready for the next job. Without an empty column you would have needed another 9 on top somewhere to park one of the 8s.

## Which column to clear first

At the start, columns 1 to 4 hold six cards each, five of them face down, and columns 5 to 10 hold five cards, four face down. That is 4 × 5 + 6 × 4 = 44 face-down cards in all. Other things being equal, the shorter columns are the cheapest to empty, and a column whose cards already form a same-suit run can be cleared in a single move once that run has somewhere to go.

## Before you deal

Because you cannot draw while a column is empty, every deal from the stock needs a plan. The stock holds 50 cards, which is five deals of ten, and each deal puts one new card on every column, possibly on top of a run you have just sorted. Before you deal:

- Make every useful move first: sort suits, turn over face-down cards and finish any runs you can.
- Then fill each empty column with the card or run that minds least about being covered. A King or a King-headed same-suit run is ideal, because it would end up in a column of its own anyway.
- If there is no King, a long same-suit run is the next best choice, since it stays a single unit underneath the new card.

## Build in suit whenever you can

When a card has two possible homes, choose the one of its own suit: put 7♥ on 8♥ rather than on 8♠. Both are legal, but only the first makes a run that can move together later. In one-suit Spider every card is a spade, so this choice never comes up; the differences between the modes are covered in [one, two or four suits](spider-one-two-four-suits.html).

## Try it

Two-suit Spider:

- Column A: J♠, then 10♥, then 9♠ on top.
- Column B: J♥, then 10♠, then 9♥ on top.
- Column C: empty.

The aim is to finish with J♠ 10♠ 9♠ in one column, J♥ 10♥ 9♥ in another, and column C empty again. It can be done in six moves. Try it before reading on.

**Answer:**

1. Move 9♠ from A into C.
2. Move 9♥ from B onto 10♥ in A.
3. Move 9♠ from C onto 10♠ in B.
4. Move the run 10♠ 9♠ from B into C.
5. Move the run 10♥ 9♥ from A onto J♥ in B.
6. Move the run 10♠ 9♠ from C onto J♠ in A.

Notice how the empty column is used twice: first to park a single card, then to hold a whole run while the other run moves past it.

Practise in [Spider one suit](../play/spider-one-suit.html), [Spider two suits](../play/spider-two-suits.html) or [Spider four suits](../play/spider-four-suits.html), and check the [glossary](../glossary.html) for terms such as run and stock.