How to Tetris

20: Single-Double

Tutorial Videos

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The Basics

Diagram Set 20-1

Single-Double is a flexible double T-spin method.

It has 2 paths. The first, more common path is to make the first T-spin a single, leading to a T-spin double. The second path involves placing the T horizontally to make a T-spin double. This then leads to an STSD.

This is the first path:

Diagram Set 20-2
12
In step 2, the player inserts the T vertically, which leads to a T-spin single line clear.
3
You get this field, which transitions to a regular T-spin double.

This is the second path:

Diagram Set 20-3
12
In step 2, the player instead inserts the T horizontally, making a T-spin double line clear.
34
You get this STSD opportunity.The player puts I and Z, making the STSD follow-up.

Common Mid-Game Chances

Single-doubles are incredibly flexible and can be used as a substitute if some other setups are not possible to construct:

1. Substituting Normal T-spin Doubles

    I have encountered this T-spin double situation way too many times:

    Diagram Set 20-4
    12
    The player easily puts a J this way to make a T-spin double.

    What if J does not come? You can instead do this by creating a Single-Double:

    Diagram Set 20-5
    12
    J does not arrive. Thus, the player puts an L vertically in step 2.
    34
    The first T-spin single concludes.The second T-spin is ready.

    In set 20-4, J may not arrive for you to make a T-spin double. Sometimes, you get an L instead, which is good as you can make the single-double in set 20-5 to get 2 T-spins!

    Advanced

    Single-Doubles have advanced variations:

    1. Spliced Single-Doubles

      A Single-Double can be stacked with T-spin triples to extend its damage. However, my experience is that it is highly redundant:

      Diagram Set 20-6
      12
      The player tops a J and T like this. This inserts a T-spin triple into a regular Single-Double.
      34
      The T-spin triple concludes. This leaves a regular Single-Double.

      This is dangerous, but makes for a spectacular method to wow your viewers if you are streaming Tetris.

      In a Nutshell

      Single-Doubles are surprisingly very practical, but they serve a niche role. They can serve as valuable substitutes to certain more straightforward T-spin double situations, if the preview pieces do not allow for the latter.

      Pros and Cons
      ProsProvides flexibility by substituting other T-spin doubles if the pieces do not allow.

      Has several ways to follow it up.

      Decent damage.
      ConsLess damaging compared to STSDs or Fractals.

      The follow-ups are clunky.

      Often not the most optimal setup in many situations; highly niche.