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 upright on top of S which makes it looks kind of like a "wing". Usually made to achieve a T-Spin Double which could then be continued with T-Spin Triple without wasting a single T 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 a single T (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 have to come before L. Perfect Clear after 14 lines is also possible.

First Bag

Mirrored Setup

Normal Setup

Second Bag

T-Spin Triple

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

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

T-Spin Double

If it is impossible to make a T-Spin Triple on the second bag, one could still continue with a T-Spin Double. The chance to stack this one is 100% because O, S and Z can be stacked in any order.

The O, S and Z pieces can be stacked in one of four ways:

It is possible to continue the T-Spin Double with Type 1 ST Stacking. Here is an example:

Form 1

3 Bag Perfect Clear

If you did the normal setup, then there is a 75.87% chance to do a Perfect Clear after 8 lines. 15 of the 18 solutions are shown. Refer to Tistory's page about Perfect DT for all solutions (see External Links).

Mirrored Setup

On the other hand, if you do the mirrored setup, then there is 74.33% chance that it could end with 8th row Perfect Clear. The probability is lower because fewer I-Spins work there.

Form 1.1

If you cannot make a Perfect Clear after 8 lines, sometimes, you can achieve a PC after 14 lines. For this form, O should come before S and T.

• 96.07%: This form is an STSD. There are two ways to stack it. Only O comes before J (first diagram). There are a few solutions where there is a T-Spin Single or Double beforehand. 21 of all 23 solutions are shown. Please refer to Tistory's page for more solutions (see External Links).

If you cannot make a Perfect Clear, then you may transition to LST Stacking.

For more stacks, refer to Tistory's page (see External Links).

Form 1.2

You are always able to stack your third bag like this; only the ZOS shape varies. However, there will be one hole clogged after the TSD.

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

In this form, 5-bag Perfect Clear is possible, but its efficiency is too low to memorize. Below is an example of how four bags might be used (93.57%):

Form 2

For this form, Perfect Clear after 8 lines is impossible, so use any of the three forms below.

Form 2.1

• 95.40%: an Imperial Cross. It is a good shape because TSD is always possible before the PC and a small number of solutions. Only S needs to come before Z and T. All four solutions are shown.

External Links

• Japanese Tetris Wiki Page explanation of Perfect DT
• Tistory's in-depth page about Perfect DT