Cut copy
From Hard Drop Tetris Wiki
An 'investing' technique where you save the T shape underneath the T-spin. Translated into English, the term means Cut Copy. The setup is also called 千鳥格子 (pronounced as chitori goushi), meaning "a thousand birds grid", whose shape is like this: http://mathnokai.up.n.seesaa.net/mathnokai/image/chidori_memo1.jpg