Tetris The Absolute The Grand Master 2 The RO Medal PLUS

Tetris The Grand Master 2 (TGM2) features six medals which can be achieved by performing a variety of tasks within a single round. One of these medals is the RO (rotation) medal, achieved by maintaining an average of at least 6 rotations for every 5 pieces. If you do this, you will receive a bronze RO medal at level 300, a silver medal at 700, and a gold medal at 999.

All rotations for all pieces count towards this medal, and it's actually possible to perform a rotation with the O-piece on every frame. Mashing the rotation buttons while an O-piece is active will make it much easier to obtain this medal.

• Sources
  • TGM2 wiki pages: Hard Drop | TetrisWiki
  • PetitPrince - TGM Guide on TetrisWiki
  • Steelix100 - TGM2 T.A. Death TAS submission
• Resources
  • ARS wiki pages: Hard Drop | TetrisWiki

Tetris 64 and its Inexplicably Obscure Rotation System

By default, Tetris 64 uses Sega Rotation, which was originally made for Sega Tetris (1988) and is the rotation system that was adapted for the TGM games. However, this game offers several options to alter how rotations work:

• Offset Turn: Enables wall kicks
• Double Turn: Enables limited 180-degree rotations, usable by double-tapping in a tight space
• Rotate Center: Enables an alternative, unique rotation system

This game really just dropped an entire rotation system that is unique to Tetris 64 and intentionally permits O-Spins via wall kicks in the second page of the options menu. In 1998. And this slipped under most of the Tetris community's radar, largely due to it being overshadowed by the Bio Sensor that was included with the game. As cool as that is, it bugs me a little that it's commonly perceived as the only thing this game added to the series.

Anyway, Rotate Center activates what I call the Tetris 64 Rotation System (T64), as it's not known to be used in any other Tetris game. This rotation system defines four distinct rotation states for every piece, including the O-piece. Because of this, the O-piece actually moves when rotated. When combined with Offset Turn and/or Double Turn, this can be used to execute genuine, developer-intended O-Spins.

While I could find some gameplay and a few discussions about this game's unusual spins, I unfortunately couldn't find any detailed information about how any of it actually works, such as the rotation states and the specifics of how the wall kicks work. I guess this is all I can say about Tetris 64, then-

So I decided to lab and document T64 (excluding the Bio Tetris polyominoes) myself, specifically for a guide about O-piece rotations.

Below is an offset chart for the O-piece in T64. The rotation states are in the middle, with basic rotations on either side. Then, each rotation has two possible wall kicks, one for each direction. The block outlined in black is the rotation centre.

Fun Fact: While not relevant to the O-piece, the left kick will always be prioritised over the right kick if both would succeed. Because of the wall kick order, this game has a mirrored form of Mihara's Conspiracy, as seen in Arika Rotation System (ARS).

Below are a few (somewhat) practical O-Spin setups. Unfortunately, the kicks in T64 limit you to clearing O-Spin Singles. O-Spin Doubles are impossible as there are no wall kicks which move the piece downwards. Additionally, spins do not award any bonus points in Tetris 64. Their main utility is to fix misdrops and to plan around the game's random piece generator. Alternatively, they're great for flexing on your spectators as their jaws drop at your stylish O-piece placement skills.

• With Offset Turn off, this can alternatively be performed with an L0R> or <L2R rotation.

• With Offset Turn off, this can alternatively be performed with a 0R2> or <0L2 rotation.
• Note how the rotation direction is the same as its mirrored setup.

• R2> must be performed quickly to complete the 0R2> rotation.
• This can also be performed with a <0L2 rotation.

• <2R must be performed quickly to complete the <L2R rotation.
• This can also be performed with an L0R> rotation.

Practical uses aside, one can have a lot of fun with O-Spins by making some silly setups. Even with such limited wall kicks, you can chain them together!

However, chaining O-Spins is tricky. Trying to do this like you can in some modern stackers won't work as there are no wall kicks that can move the O-piece vertically. Instead, you need to rely on the R and 2 rotation states being one row lower than the other two. This means repeating and following the above setups won't allow you to chain spins together as the rotation will either fail or cause the piece to move back to where it was before the first rotation.

To get around this, you'll need to create a space above subsequent kick setups, allowing you to rotate the piece back into the 0 or L state before performing another wall kick.

With enough chains, something like the setup below should be theoretically possible, allowing one to perform eight O-Spins before clearing an O-Spin Single. I'd love to see a TAS which creates and executes it.

Yeah, my brain is just like that sometimes.

• Sources
  • Lilla Oshisaure - [Tetris 64] Imagine O-Spin being a feature
    • Note that the random piece colours and spawn states are also settings in the options menu
• Resources
  • T64 wiki pages: Hard Drop | TetrisWiki
    • I didn't just lab the O-piece for this one!

Sega Tetris (1999) and Piece Joining

Ah, the one game in this guide I haven't played yet. For the time being, there isn't much I can say about it. Sorry!

In this game's Battle mode, clearing a double will cause your opponent to join the piece you used for the line clear with their next piece. The attacking piece can then rotate around it. This feature can optionally be enabled in single player, allowing you to join the line clear piece to your next piece.

• Sources
  • Sega Tetris on TetrisWiki
  • Lilla Oshisaure - [Sega Tetris (DC)] It's an O-spin! It's a T-Spin! (meme)
    • An OT-Spin Triple demonstration

Special Block Positioning

Some Tetris games feature pieces containing special blocks. If an O-piece contains a special block, it can be rotated to change its position (unless the piece is composed entirely of special blocks).

The Bombliss games (also known as Tetris Blast) have O-pieces which can be made of up to four bomb blocks, so rotation may be beneficial if the piece has between one and three bombs. There are several reasons why you would want to do this:

• Positioning a bomb on a line to be cleared will cause it to explode
• Positioning a bomb away from a line to be cleared can be useful for setting up chain reactions
• Arranging four bombs in a 2x2 square creates a big bomb, which causes a much larger explosion when cleared

Tetris Battle Gaiden features a similar mechanic with crystals, though instead of exploding, crystals are used to charge and activate your character's special attacks. Unlike Bombliss, pieces can only have up to one crystal. You may need to rotate an O-piece with a crystal to clear it with a line - it is in your best interest to gather crystals as quickly as possible due to how disruptive special attacks can be.

• Sources
  • Bombliss / Tetris Blast wiki pages: Hard Drop | TetrisWiki
  • Tetris Battle Gaiden wiki pages: Hard Drop | TetrisWiki

Audio Cues

To end the non-guideline chapter, I'd like to look at another fun use for O-piece rotations that will be impractical for most people. However, if you like beating scores in blindfolded categories, this may still be useful for you.

Compared to more recent entries, older Tetris games use very primitive rotation systems. This section will likely apply to any Tetris game with rotation SFX and no wall kicks, but I'll use Nintendo Rotation System (NRS), as seen in NES and Game Boy Tetris, to illustrate audio cues. The rotation SFX and lack of wall kicks in these games can be used while blindfolded to determine what your active piece is, at least to some extent.

The following steps can be applied in NES Tetris:

• Perform a <0L rotation, DAS to the left wall, then attempt an L0> rotation. If the L0> rotation succeeds, there is a 100% chance you have an O-piece. Yay!
• If the L0> rotation fails, move one column to the right and try again. If this still fails, there is a 100% chance you have an I-piece.
• If the second L0> rotation succeeds, perform a 0R> rotation (this will always succeed), then attempt to move the piece 1 column to the left. If this movement succeeds, then there is a 50% chance you have an S-piece and a 50% chance you have a Z-piece.
• If the movement fails, there is a 33% chance you have a J-piece, a 33% chance you have an L-piece, and a 33% chance you have a T-piece.
• Unfortunately, I don't yet know of any ways to distinguish S/Z and J/L/T. If you do, please let me know!

GB Tetris instead uses a mirrored, "left-handed" version of NRS, but the above still applies if all movements and rotations are mirrored. Beware its 18-height playfield, which will give you less time to determine your piece.

While it's not possible to play indefinitely without exceptional luck, the above steps can theoretically be used to clear a decent amount of lines before topping out.

• Sources
  • NRS wiki pages: Hard Drop | TetrisWiki