Number One

Number One is a single bag opener discovered by player Riviclia that results in a platform T-Spin Double. Thereby, the first T piece is spun into a vertical position like in STSD which makes it different from most other platform openers. It has quite some dependencies in the first bag (L after O, Z after S, J after I) but despite of its look it is a really good opener if applicable.

After the T-Spin Double
There is a single floating mino in row 2 located on the right side. However, with SRS spins it is possible to fill the area beneath it, and prepare a T-Spin Double as if the setup was just a regular STSD. Note that in diagram 3, the J piece must be spun 2 times to reach the desired location.



Instead of a T-Spin Double, these are also possible:

6-line PC
This continuation is invented by Agent RO. You can use this continuation if you get a Z piece before the O. Here, you have a 95.24% PC chance to get a Perfect Clear after 6 lines, slim chance with a T-Spin Single beforehand.

With an early I piece in the third bag, you may use the below, but since there are several dependencies (T→S→L→I and Z→O), the above is more recommended.

TST TSD PC (8 lines)
The first continuation looks like a T-Spin Triple setup but with an empty cell in row 2. So it just results in a T-Spin Double and the empty cell can be used to prepare another T-Spin. This continuation can be reached by spinning the J piece beneath the floating mino whereas there are 2 different paths; one where J is placed horizontally (diagram 3) and one where J is placed vertically (diagram 2).




 * I → O and J → S → Z (98.17% PC rate, 39 solutions)




 * I → O and J → SZ (90.40% PC rate, 13 solutions)



If making a Perfect Clear is not feasible, one can still make another T-Spin using the remains.

Imperial Cross PC (8 lines)
The second continuation involves building an Imperial Cross with the remains of the STSD. There are 2 different paths again; one involving an L-Spin (diagram 3) and the other involving a Z-Spin (diagram 2).




 * J → S and OL → Z (80.48% PC rate, 5 solutions)




 * O → J → S and Z → L (80.28% PC rate, 7 solutions)



If making a Perfect Clear is not possible, you can make a T-Spin Triple or Imperial Cross.

14-line PC
When it comes to 14 lines, there is no definite way. Below is an example with three Imperial Crosses and a 99.96% PC chance.