Skimming is a method where a player does a non-Back-to-Back line clear to make the stack more favorable. This page will focus more on skimming used for offense in the current guideline Tetris.
In modern Tetris, skimming has a couple of utilities:
- As mentioned before, the point of skimming is to lead the field into a more favorable stack. This gives the player more choice on how to place the subsequent minos, such as building a TSD.
- Line clears mean a lower overall stack. A lower overall stack implies the ability to accept more incoming garbage lines. This is good for temporary defense.
However, skimming has three critical drawbacks:
- The player loses Back-to-Back.
- Non-Back-to-Back line clears inherently have lower attack efficiency.
- The player has to deal with an added line clear delay.
Therefore, skimming is not optimal for attacking and should be reserved as a defensive measure.
Due to how minos are structured, there are several groupings of minos that serve identical functions for skimming.
Looks like this. You can achieve the same field with T or J.
The most commonly used TSD skimming looks like this. You can achieve the same field with an S instead of an O. Not too bad because the double line clear sends 1 line, and the TSD restarts Back-to-Back.
These are some other skimmings that are relatively often used, mostly as a compromise for not having the right pieces.
Here are some other situational setups.
These are some named skimming techniques that result in a TSD. You'll probably encounter these every once in a while.
貫の技法. This skimming pattern with an I is useful to know.
For this example, you would be rotating the I mino counterclockwise twice.
WC鋤の刃. Useful when you need to do a TSD as soon as possible, but you don't have the right mino to complete the TSD shape in certain situations, e.g., in a field like below where you don't have an I coming soon.
You could also turn this into a TSS donation technique, but this would only be applicable in pretty specific situations.
デジャヴ. Mostly used for downstacking instead of building a TSD because a Tetris is usually a better option if you're trying to attack. Line clearing this way is also used in some perfect clear solutions, such as the ones for MKO.
Consider it in a situation like below where sliding in the L would take too long. Since this soft drop is tricky, people often miss it and do this technique involuntarily anyways.
These are used when you have to lower your stack ASAP.
Used when you don't have a T coming soon to do the TSD. A common situation would be having to do this instead of completing the second TSD of STSD because you have to get down quickly.
Needless to say, using an I here to clear lines would result in a bad stack.
Works even when you have a TD setup.
スイッチ. Used when you are at the very top of the board. This preserves the TSD slot and an overhang while allowing you to accept 1 more line. You can also use it to extend combos to combo into a TSD.
This section has some links that mention the term "Prophecy" and "Forecasting," which can be confusing because they have the same dictionary meaning.
Prophecy T-Spin involves setting up a T-Spin overhang in advance. That's all it means. Forecasting a T-Spin means that a player stacks in a way where T-Spin slots will emerge after line clears. One way to forecast a T-Spin is to utilize skimming. Using Back-to-Back line clears to forecast a T-Spin would be bigger brain.