The BT Cannon, where the letter "B" stands for "beta", is a Double Triple setup invented by a Japanese player TCM-β. It uses a good balance of pieces and it looks beautiful. The important foundation is an early I-mino.

Basic Opening

Opening 1

Opening 2

Special β ●-hiro

After the Triple

With the remaining hang, you can even stack and transition into a 4-wide combo.

BT Cannon C-Spin

The following setup was invented by a Japanese player going by the name 26_nameless. This particular setup is almost always possible, depending on the order of the pieces in the second bag. The setup also has multiple Perfect Clear opportunities that end on the end of the fifth bag, meaning the setup can be made again. There are more ways to use the third and fourth bags than are shown.

IT Base

First Bag

Second Bag

T-Spin Double

T-Spin Triple

Third Bag

Fourth Bag

T-Spin Triple

T-Spin Double

Make an S-Spin

Perfect Clear

TLJ Base

First Bag

Second Bag

T-Spin Double

T-Spin Triple

Third Bag

Fourth Bag

T-Spin Triple

T-Spin Double

Make an S-Spin

Perfect Clear

BT Cannon C-Spin In-Depth

First Bag

Second Bag

Third Bag

Fourth Bag

Options depending on how the stack looks after 3 bags:

Fifth Bag

Trinity / STSD is an option:

But Perfect Clear is usually better:

generic PC rate	99.9%	93.3%	94.0%	69.6%	84.0%
T on bottom	97.1%	91.6%	83.6%	62.8%	63.6%

displayed PC chances are under the assumption that the first piece of the sixth bag is put on hold, thus not used in the setup

T-Spin Double into Perfect Clear is very likely when T piece comes early in fifth bag:

Setup #1:

Setup #2:

Setup #3:

Setup #4:

Setup #5:

Note: For every PC build with horizontal I piece in the top right corner, there's an equivalent build with I piece one row lower (usually splitting the S + Z combination). Also note that all builds of setup #3 are contained in #1 and all builds of setup #4 are contained in #2.

BT Cannon STSD

See also

• Twists
• DT Cannon - another technique that results in a T-Spin Double followed by a T-Spin Triple