Anchor Set (アンカーセット)
A rarely used technique that is utilized in order to maintain Back-to-Back. Given its name because the J kind of looks like an anchor.
In a traditional sense of using Anchor Set, you would stack up a Tetris after anchoring the J. You do need to be consious of how you stack, or else the open column underneath would remain covered.
Compare with how you would normally clean up the TST overhang by softdropping and sliding in a L or a J. In contrast, notice how no softdrop was required in the above example involving Anchor Set.
Placing the J for Anchor Set, assuming that you intend to maintain Back-to-Back, effectivley means that you will be committing to stacking 4 more lines to follow up with a Tetris. When you slide in a L, you only have to stack 3 more lines in order to follow up with a Tetris. This means that you'll remain vulnerable to attacks for a longer period of time when you use Anchor Set in most cases.
- Tetrisch on Anchor Set