Centre 4-wide: keeping a combo going in a four-column well

Centre 4-wide keeps a combo going in a four-column well: why each piece clears a row and how to spot a good leftover, based on a check of every pattern.

October 5, 2026

Centre 4-wide is a way of stacking in which you leave a well four cells wide in the middle of the board, stack the left and right sides high, and clear one row with every piece you place in the well. A line clears with every piece, so the combo runs to 10, 15 and beyond. Unlike a setup, where you memorise a shape, it asks for a decision on every move: “leave a shape that can be cleared again next time”. This page explains how to make that decision. For how combos are counted, see “Line clears and scoring”.

Why one piece clears one row

Use three columns on each side as walls and leave only the four centre columns open. Leave just three cells of blocks at the bottom of the well.

The well is four cells wide. To complete a row, all that is needed is for its four cells inside the well to be filled. If you leave three cells at the bottom in advance, every four-cell piece you place brings the blocks in the well to seven cells in total. Four of them clear as one row, and three are left once again.

In other words, it is a loop: “three cells are left → place one piece → one row clears → three cells are left again”. The shape of the three leftover cells changes every time. Whether that shape can take the next piece decides whether the combo continues.

One move as an example

The S cannot go straight in, because its bottom-left cell sits under the overhang. Turn it clockwise to stand it up, drop it into the well, then turn it clockwise once more at the bottom: it settles on the dotted outline and the second row from the bottom clears. What remains is three cells at the bottom.

The shape after the clear. The three cells now lie flat along the bottom.

Before you place a piece, “does this piece complete a row?” is not the only thing to look at. Look as far as “which three cells will be left once it clears?”

Good leftovers and bad leftovers

Using this site’s engine, we checked every shape the three leftover cells can take. The number of piece types that can keep the combo going differs greatly from shape to shape.

Good leftover ①: an L shape pushed against one wall. Six of the seven pieces (I, O, T, Z, J, L) can continue.

Good leftover ②: flat along the bottom with just one cell open. Six pieces (I, T, S, Z, J, L) can continue.

The starting shape (one cell at the bottom with two cells above it). Five pieces (I, O, T, S, Z) can continue. J and L cannot clear a row.

Bad leftover: a pillar standing in the middle of the well. Only the I can continue.

Good leftovers have things in common.

Low. The three cells sit within the bottom one or two rows.
Against a wall. The blocks are at the edge of the well, and the empty space is all in one piece.
No pillar in the middle. When blocks stand up in the middle of the well, the empty space is split into left and right and pieces no longer fit.

How to keep the combo going

1. There are always two pieces you can place

Even if the current piece does not fit, the piece in hold, or the next piece when hold is empty, may fit. In centre 4-wide you keep using hold as “a shelter for the piece that does not fit”. J and L do not fit the starting shape, so if a J or an L arrives, put it in hold.

2. If two placements clear a row, choose the one with the better leftover

Even the same piece leaves a different shape depending on how you place it. If either way clears a row, choose the one whose leftover is low and against a wall.

3. Look at the next preview and leave a shape that the next piece fits

The piece that comes next is visible in the next preview. When you have a choice of leftovers, leave the shape that the next piece can continue from. Once you can do this, your combos start reaching double figures.

How to build the well

To build a centre 4-wide from the opening, stack the pieces of the first and second bags in the three columns on each side, and put just three cells at the bottom of the well. The three columns on each side can be stacked high without holes by combining the “rectangle three cells wide and four high” made of L, O and J with I pieces stood upright.

The higher the walls on each side, the longer the combo lasts. With walls ten rows high, you can clear about ten times in a row at most. While you are stacking you cannot send any attack, and if your opponent’s attack arrives the well gets filled in, so in versus play you also need to judge “whether you can finish stacking”.

The “Centre 4-wide Drill” starts with the well and the first three cells already in place. The walls on each side are topped up by as much as was cleared, so you can keep going as many times as you like until you make a mistake. Start by aiming for ten in a row.

Practice this