Original Rotation System

The black dot marks the segment of the piece which spawns in row 20 column 6. It's also the axis of rotation (except for the O piece, which doesn't rotate).

The Original Rotation System is the rotation system used in Tetris (Electronica 60) and Tetris (IBM PC).

It is identical to Nintendo Rotation System, right handed version, except that the horizontal orientation of the I piece is one block higher.

Games using this rotation system generally have no wall kick, lock delay, no ARE, and depend on keyboard repeat rate for their DAS.