T-spin basics: the T-spin double

The conditions for a T-spin, plus the shape of the T-spin double (TSD) slot, how to build it and how to spin the T in, move by move with board diagrams.

October 5, 2026

A T-spin is a move that fits a T piece into a gap by rotating it. The T-spin double (TSD), which clears two lines at once, gives more points and more attack than a Quad from a single piece, which makes it the gateway to intermediate play. The goal of this page is to learn just one TSD shape that you can build and fill reliably.

A quick review of how it is detected

There are two conditions for a T-spin.

The last action before the T piece locks is a rotation.
Of the four diagonal cells around the centre of the T, at least three are filled (walls and the floor count as filled).

The four red cells are the diagonal cells around the centre of the T. If three or more of them are blocks, walls or the floor, it is a T-spin.

So a T-spin shape is a spot where the T fits exactly and three of its diagonals are blocked. The T cannot get there just by falling from above, so you put it in with a rotation.

A TSD slot is made of three parts

The basic T-spin double shape. Memorise it as a whole.

Lower row: a one-cell notch. This is where the nub of the T goes.
Upper row: a three-cell gap centred on the notch. This is where the bar of the T goes.
Overhang: one block directly above one end of the three-cell gap. This fills the third diagonal cell.

Leave the side opposite the overhang open as the entrance for the T. The two lower rows must be completely filled apart from the four cells the T will occupy. If any column is left unfilled, you still get a T-spin, but the two lines do not clear.

Putting it in: drop it upright, then rotate once at the bottom

① Turn the T upright (nub pointing away from the overhang) and soft drop it through the entrance to the bottom of the notch. Do not hard drop.

② Once it reaches the bottom, rotate once in the direction that points the nub downwards. The T tucks in under the overhang. Lock it there and you have a T-spin double.

When the overhang is on the left (as in the figures above), you rotate clockwise twice: the first rotation turns the T upright in the air, and the second tucks it in at the bottom. When the overhang is on the right, everything is mirrored, so you rotate counter-clockwise twice.

The key is to rotate after the T has reached the bottom. If you do both rotations in the air first, the T lands on top of the overhang and never enters the slot. Once it has rotated in at the bottom, lock it straight away with a hard drop, with no other input in between.

How to build the overhang

An overhang is a block that sticks out with empty space under it, so it does not appear by itself in ordinary stacking. You build it on purpose, using the part of a piece that sticks out. The easiest way is to stand a J or an L upright against the wall.

Stand a J upright at the left edge and the cell sticking out at its top becomes the overhang. At the right edge, an L makes the same shape.

The top half of an S or Z, the end of a flat L or J, and any other part that sticks out sideways by one cell can serve as an overhang too. Remember it as “next to the notch, build a ledge with one empty cell under it”.

Common mistakes

No overhang

With no overhang, the T drops straight in from above. Only two diagonal cells are filled, so it is just an ordinary Double.

Blocking the entrance

If you place a piece directly above the notch, the T can no longer get in. Once the slot is built, put nothing in that column until the T arrives. If the T is not coming soon, stack the other columns flat while you wait.

The lower rows are not completely filled

When you concentrate on building the slot, a hole can be left in a column far away from it. Before putting the T in, check that both lower rows are completely filled.

Waiting for the T piece

With 7-bag, only one piece in seven is a T. If the T is far away when the slot is finished, your stack grows while you wait. So if a T arrives before you have built the slot, store it in hold. Bring it out of hold the moment the shape is ready and there is no waiting at all.

The “T-spin double” setup drill lets you practise spinning the T into the slot from this lesson; you can also pick a form where you build the overhang yourself. In Basic Practice, “T-Spin Double” appears on the board when you land one. If it only says “Double”, the overhang was missing.

Practice this