TETRIS GLOSSARY
Back-to-back
Also called B2B · BTB · Back to back
A chain of qualifying difficult clears, commonly Tetrises and T-spin line clears. Under common modern rules, non-clearing placements preserve it; an ordinary Single, Double or Triple breaks it. Eligibility and bonuses vary by game.
View in the A–Z glossary →Tetris → No clear → TSD
Under common modern rules, the non-clearing placement preserves B2B. An ordinary non-spin Single would break it.