[Coda]

It shut down at around the same time that Tetris 99 picked up game modes beyond just battle royale... which is to say, recently.

A T-spin was originally a game mechanics exploit that would let you rotate a T piece into a place under an overhang that it wouldn't normally be able to reach. Basically, if a rotation (possibly also including gravity and wall kicks) would put the piece in a legal place, then the piece would go there, even if it would have to have clipped through another block if the rotation were smoothly animated instead of a sharp 90-degree snap. This enables some surprisingly nuanced gameplay, so instead of being patched out it was promoted to an actual feature. (I'm sure the fact that patching it out would have been hard probably also had something to do with it.)

Clearing a line with a T-spin counts for twice as many points and twice as much multiplayer trash. This means that the most valuable move in the game is a T-spin triple: if you slip a T piece into a hole that lets it clear three lines at once, it's worth 1.5x as much as a Tetris.

The T-spin technique can be used with any block (except O, because O blocks don't meaningfully rotate) but only T gives a bonus.