The BT Cannon (BT砲), 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.
Some more continuations:
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 and 4-Wide Combo Setups are options:
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:
Other Variations
These are less explored setups starting on the fourth bag, but still have similar Perfect Clear chances as the setups outlined above.
PC Continuations
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.
TSM to BT
It is possible to make a BT Cannon without wasting a T piece. Here, a T-Spin Mini Single is used to make the offset hole. In the second bag, T must be held until the third bag. The third bag can be stacked in any way. If T comes early in the third bag, then do a TSD. Below is an example of a 14th row PC setup:
Mid-game BT Cannon
Even though it is hard to spot the opportunities on making a BT Cannon mid-game, it has the same benefits as making a DT Cannon.
Kaidan Alternative
There are many ways to make a mid-game BT Cannon, but the easiest pattern to spot is to look out for pattern similiar to the field shown below.
So basically, aim for a pattern with at least a block on one side of a hole and 3 steps of "staircase" on the other side of the well. Similiar to the base needed to execute the Kaidan technique. See the field below for the comparison between BT Cannon and Kaidan by using the same base (Kaidan on left; BT on right).
Parapet Conversion
This form could also be made by converting a Parapet. You could also see BT cannon as just Parapet but with extra steps.
Cut Copy Alternative
For example, 2 garbage lines that looks like the situation below got sent.
Making a Cut Copy like the example shown below is usually the most recommended way to deal with those holes to achieve two T-Spin Doubles.
But depending on the NEXT panel, making a BT Cannon is much more powerful in terms of the firepower.
BTD Attack
For garbage holes that looks like the terrrain below, making a BT cannon is better than other setups. It basically leads to TSD-TST-TSD. Since the latter form is basically a Triple Double Attack, calling it a BTD cannon is good. This form leaves a neat terrain.
BT Cannon STSD
See also
- Twists
- DT Cannon - another technique that results in a T-Spin Double followed by a T-Spin Triple
External links
- in-depth analysis of BT Cannon -> C-Spin -> 14th row PC loop
- video of BT Cannon -> C-Spin -> 14th row PC loop
- in-depth analysis of mid-game BT-Cannon, specifically Cut Copy Alt. and BTD Attack along with some more.
