The Nine-Column Stack and the Open Well

Fill nine columns flat, leave one open, and wait for the long piece. The standard shape for a high score.

The classic scoring formation: build nine columns to an even height and leave one column completely empty. When the well is four rows deep, drop an I piece into it and clear four rows at once.

Why it works

A four-row clear is worth 800 base points against 100 for a single, and with back-to-back live it becomes 1200. Nothing else in the scoring table competes.

The formation exists because it is the only way to set up that clear repeatedly.

Which column

Convention puts the well at the far right or far left, which is why you will see this called the nine-zero stack: nine columns of stack, zero in the well.

An edge well is easier to maintain because it has only one neighbour, so fewer pieces can accidentally spill into it. The right edge is marginally more common purely because most rotation systems make it slightly easier to slot an I there.

A well in the middle of the board is possible but much harder to protect.

The discipline it demands

Never put a piece in the well. This sounds obvious and is the single most common failure. Under time pressure, with a piece that fits nowhere else, the well looks like free space. It is not: filling it costs you the entire setup.

If a piece genuinely will not go anywhere else, place it badly on the stack. A lumpy nine-column stack still has a well. A flat ten-column stack has nothing.

Keep the nine flat. The point of the well is that the other nine columns clear together. If they are uneven, an I drop clears one or two rows instead of four.

Do not build too high. Four rows deep is a clear. Eight rows deep is not twice as good; it is the same clear with twice the risk of topping out while waiting.

When to abandon it

If the long piece came out early in the current bag and the stack is already high, stop deepening. Take a double or a triple, get the height down, and rebuild. A well you die next to is worth nothing.

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