Perfect DT

Perfect DT (Perfect Double Triple / パーフェクト DT) is a setup invented by a Japanese player named Yuu. It resembles a TKI 3 Opening but with the L placed vertically on top of S which makes it looks kind of like a "wing". It is usually made to achieve a T-Spin Double which could then be continued with a T-Spin Triple without wasting any T's and usually ends with 8th row Perfect Clear. This is one of the only discovered setups that could achieve 8th row Perfect Clear without wasting any T's (other setups like Albatross Special and Pelican could only do Perfect Clear after 10 cleared lines). This setup could be made with an early I and S. I have to come before S, then L. Perfect Clear after 14 lines is also possible.

T-Spin Triple
This setup is usually continued by a T-Spin Triple. Notice how JI and LO could be swapped which increases the overall chance to get a T-Spin Triple without wasting a T. It uses an unusual overhang but it works nonetheless.

If J comes early but Z comes before I, you could still create a T-Spin Triple with Z placed vertically on top of J.

T-Spin Double
If making a T-Spin Triple is impossible, you can make a T-Spin Double, which is always possible since the O, S and Z pieces can be placed in any order.

It is possible to continue the T-Spin Double with ST Stacking.

3rd Bag Perfect Clear
In the normal setup, you have a 75.87% PC chance and 15 solutions.


 * On the other hand, in the mirrored setup, you have a 74.33% PC chance. It is slightly lower because it is impossible to place the I piece in the below situation.

Form A1
If you cannot make a Perfect Clear after 8 lines, you may try to achieve a PC after 14 lines. For this continuation, O should come before S.


 * O → J / L → I → J → O (96.07% PC rate, 21 solutions): It is an STSD. You have two ways to stack it.

You may use LST stacking if you decide to abandon the Perfect Clear chance.


 * Z → J and L → O or O → L / O → J and ZL → I (96.11% PC rate, 15 solutions): You have three ways to stack it, but you will never be able to make a T-Spin and Perfect Clear at the same time.

Below are examples of a T-Spin that can be made from this form (the second example shows an STSD).


 * IZ → L → O (99.13% PC rate, 24 solutions): Despite a high Perfect Clear chance, the number of solutions makes this continuation slightly unsuitable. Therefore, it is better to make another T-Spin.

It is easier to make a T-Spin Double in these two ways, but you can stack freely.

Form A2
You will always be able to stack this continuation, but you will still have a clogged hole afterwards.

Use the fourth bag to open the hole. Some examples (the fourth example shows forecasting):

A 5-bag Perfect Clear is possible here, but it is better disregarded. For instance, the below has a 93.57% PC chance and 6 solutions.

Form B (T-Spin Triple B)
You cannot make an 8-line Perfect Clear in this form, so make another T-Spin Double in these three ways.

Form B1
If you get an early O, the ideal form can be used.


 * S → Z (95.40% PC rate, 4 solutions): The best continuation overall is an Imperial Cross. You can mostly get a T-Spin Double before the Perfect Clear.


 * Z → S and JO → L (99.88% PC rate, 9 solutions): You have a very high Perfect Clear chance and a few solutions, but you will never be able to make a Perfect Clear and a T-Spin at the same time. This form is good for T-Spins if Perfect Clear is unneeded.

You can make a T-Spin if you choose to forgo the Perfect Clear chance. The fifth and sixth examples show King Crimson and T-Spin Triple respectively.


 * JO → I → L (100.00% PC rate, 26 solutions): Even though the probability is 100.00%, the Imperial Cross form is still better. The disadvantages are that you cannot make a T-Spin and Perfect Clear together and there are too many solutions.


 * Z → OJ and S → L (54.29% 12-line PC rate, 7 solutions and 33.33% 14-line PC rate, 2 solutions): You get a low PC chance, but the tradeoffs are a flat surface and a few solutions.


 * 12 lines (54.29%):


 * 14 lines (33.33%):

You can use King Crimson if making a Perfect Clear is not achievable.

Form B2
If you have an early S, you can use this form. Unlike the Form B1, it is harder to make a Perfect Clear setup.


 * S → Z and L → O → I (28.89% PC rate, 1 solution including α): You can do a T-Spin beforehand. If you cannot get a Perfect Clear, simply continue with another T-Spin.

If you cannot get a Perfect Clear, you simply make another T-Spin. The third example is a TST tower with a T-Spin Single beforehand.


 * Z → J → O (51.55% PC rate, 5 solutions): It is possible to make a Perfect Clear, but it is better to make a T-Spin.


 * Z → J → L (16.67% PC rate, 1 solution): Rather than Perfect Clear, a T-Spin is still better.

Form B3
If you cannot make any of the two continuations above and instead get an early Z, you can use this.


 * J → O (54.29% 12-line PC rate, 7 solutions and 33.33% 14-line PC rate, 2 solutions): The solutions are the same as the last form in Form B1.

You can make a T-Spin in other ways.