SBSD

Originally created by Wertj

Super Beta Spin Double (or abbreviated, SBSD) is a double T-Spin Double or sometimes, a T-Spin Double to STSD opener. However, there are many variants as the second bag can be tricky when it comes to building on top of the first bag. The setup relies on a late T as the T is what one will hold from the first bag and use the second bag to build the second layer according to the variants. Additionally, the first bag requriements are the same as MKO Stacking, therefore, it is interchangeable with the latter setup. Although the main name of the setup is Super Beta Spin Double, the community often refers to it as Shadow-Blade Spin Double, named after a notorious Reddit poster as the idea of the setup was sparked by him.

First Bag
Both L and J are needed before Z and S.

However, if L comes after Z but before O, then it can be assembled like below.

Perfect Clear
There are two solutions to get a 4-line Perfect Clear. For both solutions, the top two lines must be cleared before placing T on the bottom.

SBSD ZS variant
The ZS stands for the piece that makes the T-shaped hole in the second bag. In this case, depending on which side one uses, the Z and S is used.

Overhang Choices
The T overhang should be used as a last resort because the shape that is left afterwards will be unstable.

Ways to fill in the gap
It is preferable if one can use any of the first three diagrams. The last two diagrams should be used as a last resort because the shape is unstable.

Continuations

 * T-Spin Triple


 * Perfect Clear after 6 lines

JS variation

LJ/O variation


 * Perfect Clear after 8 lines: If one gets O early and stack like below, then there will be a 97.70% chance of making an 8-line Perfect Clear afterwards. All solutions require placing the I piece on the left.

SBSD LJ variant
The LJ stands for the piece that makes the T-shaped hole in the second bag. In this case, depending on which side one uses, the L and J is used.

Overhang Choices
The T overhang should be used as a last resort because the shape that is left afterwards will be unstable.

Ways to fill in the gap
It is preferable if one can use one of the first two diagrams. The last three diagrams should be used as a last resort because the shape is unstable.

Continuations

 * Perfect Clear after 8 lines: This one has a 45.75% PC chance.

SBSD E2bT variant
In this case, E2bT stands for early second bag T as there is only 1 possible early second bag T situation that is viable which is in the LJ variant. This should only be used as a last resort as it is highly ineffecient.

Main shape

Common builds
TSS stands for T-Spin Single, so one makes the shape, T-Spin Single then add the S (Remember that the opposite always applies when doing the setup from the left side).

SBSD ZK variant
The ZK variant is named after Zack101155, Bassistunietd0's friend. He was the one who found this variant while testing the setup in 20TSD mode. In this case. An S/Z piece is added in a unique way to create a new T shaped hole.

Continuations

 * Perfect Clear after 6 lines

 LJ variation


 * Perfect Clear after 8 lines: If one gets an L before Z and O, then the below is possible. It will result in a 96.47% chance of a Perfect Clear.

Replacing TSD with STSD
If one does not pre-stack the overhang for the second TSD, they can make an STSD in 2 ways.