Arika Rotation System

TGM rotation is a game play mechanic used in Tetris The Grand Master and other Arika tetromino games, derived from Sega rotation.

Games using TGM rotation generally use IRS, fast DAS, lock delay, and firm drop, and tetrominoes start out with the topmost block on the top row (generally row 20). Tetris The Grand Master Ace uses a hybrid of TGM rules and Guideline rules.

Basic rotation

TGM's basic rotations inherits most of its properties from Sega rotation, which was used in most previous Japanese arcade Tetris games. Some defining design choices include:

• Having 2 (as opposed to 4) rotation states for S, Z, and I tetrominoess to simplify learning.
• Keeping tetrominoes at an even level while rotating to always allow rotation when the tetromino is on a flat surface (except for the I tetromino - see exceptions below).
• Pointing the initial stance of the T, L, and J tetrominoes downward to add some extra challenge and also make it easy to have tetrominoes grab bumps along the surface of the stack when playing at high gravity.

TGM's basic rotations.

Wall kicks

TGM pioneered the use of wall kicks, with simple but effective kick rules. These rules were unchanged until TGM3, remaining constant across TGM, TA, TAP, and Sakura Tetris. Up to 3 locations are tried, in this order, before rotation will fail:

• Basic rotation
• 1 space right of basic rotation
• 1 space left of basic rotation

In addition to these rules, there are some extra exceptions where certain wall kicks are not allowed:

• The I tetromino will never kick.
• L, J, and T tetrominoes will not rotate in the situations illustrated below if the marked block is occupied.

• However, L tetrominoes will rotate clockwise and J tetrominoes counterclockwise in the situations illustrated below if both the marked blocks are occupied.

New wall kicks in TGM3

I tetromino's wall kicks

In TGM3, the I tetromino can kick walls. There are 3 different types of wall kicks.

Try to rotate	Basic rotation fails	Kick 1 space right
Try to rotate	Basic rotation fails	Kick 2 space right
Try to rotate	Basic rotation fails	Kick left

I tetromino's floor kicks

The I tetromino can kick the floor.

Notes:

• Like hold piece, floor kick can be performed only once per tetromino.
• This action causes lock delay reset.
• The tetromino cannot kick the floor in mid-air.

Fail

OK

OK

There are 2 different types of floor kicks.

Try to rotate	Basic rotation fails	Kick 1 space up
Try to rotate	Basic rotation fails	Kick 2 space up

T tetromino's floor kicks

The T tetromino can escape from a hollow.

Notes:

• This action can be performed only once per tetromino.
• This action causes lock delay reset.

Try to rotate

Basic rotation fails

Kick up

To-Do

• describe ACE's ARS and ARS2
• describe "Mihara's conspiracy"
• mention right bias
• add more visual aids?

References

• KAN's detailed explanation of TGM3's new I and T floorkicks
• TGM rotations, in Japanese