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. First invented by MalaiABUeditor.

If you get an early I in your third bag, the below stack may work, but has piece dependencies, so the above is better.

TST TSD Perfect Clear
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 vertically and the other path involves the J piece horizontally.

Path 1: 98.17%

Path 2: 90.4%

If Perfect Clear is not possible, one may do any continuation below.

Imperial Cross Perfect Clear
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: 80.48%

Path 2: 80.28%

If Perfect Clear is not possible, one may do any continuation below.