Number One

Number One is a T-Spin Opener invented by Riviclia. Here, the T piece is spun vertically like in STSD.

After the T-Spin Double
After the T-Spin Double, there is a floating block at row 2, column 9. With SRS spins, it is possible to fill in the surrounding empty space and make another TSD. Some examples:

Some advanced techniques:

6-line PC
If you can stack the right side like in the leftmost diagram, there may be a chance for a Perfect Clear after 6 lines. Sometimes, you do a TSS before the PC. There is no way to get a PC with a TSD.

TST TSD Perfect Clear continuation
This Perfect Clear continuation is stacked like a T-Spin Triple, but with a gap. There are two paths, the first path involves the J piece horizontally and the other path involves the J piece vertically.

Path 1

Path 2

Imperial Cross Perfect Clear continuation
This continuation is an Imperial Cross for a Perfect Clear. Again, there are two paths, the first path involves the L piece being spun and the other path involves the Z piece being spun.

Path 1

Path 2