From Hard Drop Tetris Wiki
The Nintendo Rotation System, or NRS, is a rotation system divided by two variants. The right-handed version was used in Nintendo's NES Tetris game and Tetris & Dr. Mario. Tetrominoes spawn with their highest block on row 20.
Left-handed version was used in Tetris (Game Boy). Tetrominoes enter with their highest block on row 17.
Games using this rotation system generally have no lock delay.
This rotation system is wallkickless.