Double Triple Cannon Setups

Double Triple Cannon, sometimes referred to as DT Cannon or DT (known as DT砲 in Japan), is a T-Spin combo designed by player TKI. The setup is essentially a T-Spin Double followed by a T-Spin Triple. A player utilizes the T-Spin Triple wallkick in SRS to make a T-Spin Double that leads into a T-Spin Triple. In Tetris variants without instant lockdown it is best to hold the soft drop button until the T-Spin Double has been completed. This makes it instantly drop "through the gap" so the T tetromino does not rotate early and end up in the wrong spot.

Empty Field Setups
Because so many DT Cannon setups exist, the player can choose a setup that fits the order of their opening bag of pieces. It is usually possible to hold a T through the second bag and into the third, allowing the player to make both T-Spins in quick succession.

TKI's Signature

IT Balance

TZ Base Setups

JO Base Setups

IL Base Setups

JL Base Setups

DT-Cannon with no T Pieces

In this setup, the player tries to use no T pieces to set up their DT-Cannon. It is only possible to clear this setup within 14 pieces if the second T is at the end of the second bag, but, if successful, this is the fastest DT-Cannon setup (in terms of piece efficiency, other setups may be faster to execute - see Efficient DT-Cannon Openers section below). Otherwise, the second T will be used for the upstack, reducing this setup's efficiency to the same as the rest listed here.

Other Setups

Efficient DT-Cannon Openers

With the right set of pieces (one of L/J needs to come before S/Z, both if T comes too early) DT-Cannon can be stacked with very few key presses by taking advantage of two-step finesse. Even though a T piece is "wasted" in the stack, this build can be performed faster than many builds that are more piece efficient (such as Albatross or C-Spin), thus making up for the extra pieces placed. In fact, having more pieces in the stack can sometimes be advantageous, because they can more quickly be transitioned into a 4-wide stack or a Tetris stack. The mirror with cannon on the right side uses more key presses, so it should be stacked on the left for optimal efficiency.

Depending on the bag, the alternate form might be needed.

The JZ Base DT Cannon results in the same stack but needs more key presses. The second bag is usually placed in one of the following ways. Sadly, none of them will work with certain piece combinations involving early T and S pieces (e.g. TSIZ).

Continuations
DT-Cannon is one of the most versatile openers and can be followed up in almost any style of stacking. DT-REN and DT-PC are thought to be some of the best counters to the dreaded 4-Wide opener.

T-Spin Double

Side 4-Wide (DT-REN)



Tetris stacking

Perfect Clear followup (DT-PC)

There are of course many ways to set up a PC continuation, but this way has a high success rate and is probably the most commonly employed method (as popularized by pro Japanese players like amemiyataiyou100). After the two T-Spins, use the five previews to figure out the PC. Some examples:

Some more stacks that can result in a Perfect Clear after 10 lines:

And 2 stacks that can result in a Perfect Clear after 8 lines. The chances are very slim though.

C-Spin followup (DT-TKI)

Some stacks that can work as a base for the C-Spin / Triple Double Attack:

If T comes late in the third bag but a C-Spin base could be made with the other pieces, one could hold the T piece to do the C-Spin TST before doing the bottom TST. Which then could be continued into a T-Spin Triple Tower. Since only a single piece is needed after making the C-Spin base to complete the TST in the fourth bag, the chance to be able to make a T-Spin Triple Tower without wasting a T is quite good.

DTDT Cannon

DTDT Cannon, which is called "DT砲の組み替え" (lit. DT Rearrange) in the Japanese community, is a rare way for people to continue a DT cannon with another DT cannon on the opposite side of the board. Just like DT-TKI, the T-Spin Triple that was built on the second bag have to be done early on the third bag. Z also have to come before O.

Here are some other ways to stack:

TZ Base Continuations
The DT Cannon with the TZ Base is one of few DT Cannons that will work with early T, S and Z pieces. The second bag is usually placed in one of the following 4 ways. The OI overhang gives the best results.

Here are 2 stacks that may result in a Perfect Clear after 10 lines:

In case of the OI overhang there is also a T-Spin opportunity on the right side. Ideally, the T piece comes early in the third bag. C-Spin is also possible.

This may also give a small Perfect Clear opportunity after 8 lines.



In the first bag the J piece can also be placed vertically. This makes the I piece placement less problematic in the second bag and the same stack can be reached by 2 different placements of the S, Z and O pieces.



Here are some continuations for this J piece placement. C-Spin is also a possible continuation.



Higher Notch
Line Clear Shaping

DT STSD
This setup looks identical to DT Cannon, with the only difference that one further cell is empty at the bottom (marked light grey in the first diagram below). It results in an STSD after the first T-Spin Double is cleared. So, it is usually 3 T-Spin Doubles in total.

DT STSD has the advantage that no overhang will be left after the last T-Spin. A regular DT Cannon has the advantage that it is easier to build, faster to execute and that one can build a 4-wide on top of it. However, receiving a garbage line with the hole in the wrong column will break the execution of the STSD. As opener, it may be actually better to stack it with an additional line below (see second diagram below). The third to fifth diagrams below show a combined setup that results in 4 T-Spin Doubles.

Similar DT Attack
The S piece takes over the place of the O piece. One must execute the T-Spin Double before the J piece can be placed on the left side. This setup has the disadvantage that it takes more time to soft-drop the T-pieces, that the T-Spin Double can not be held back and that the 2 T-Spins cannot be chained in one combo.

However, one of the first 3 openers shown below will always work for the first bag when the standard DT Cannon openers are not available. Also note that if the first T piece is placed upside down, then those 3 setups result in the exact same stack as that standard DT Cannon where the T piece is placed first (surrounded by S and Z). In the fourth diagram one sees an SZ Double Triple which does not necessarily require to place a T piece on the stack.

Alternatively to the second and third diagrams above, the position of the I piece can be switched with the LSJ block (see 2nd and 3rd diagrams below). This allows to place the second bag always like shown in the fourth picture below (SZOIL can be placed in any order - sometimes requiring an S-Spin; J must be kept on hold until after the T-Spin Double). The advantage of this setup is that it can be continued with a C-Spin very easily.



Dulse Flame (Darth Flame)
This opener starts with a T-Spin Mini that is used to stack a further line below a DT Cannon (third picture below). That further line allows to clear a further T-Spin Double with the overhang that is left after the execution of the DT Cannon. After the first T-Spin Double is cleared, it resembles a [[Triple Double Attack Setups|Triple Double Attack] (fifth diagram below).