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Tetris: The Grand Master

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Title Screen

Tetris: The Grand Master

Also known as: TGM, TGM1
Developer: Arika
Publisher: Capcom
Platform: Arcade (Sony ZN-2)
Released internationally: December 1, 2022 (Arcade Archives)
Released in JP: August 1998

CodeIcon.png This game has unused code.
CopyrightIcon.png This game has hidden developer credits.
DevTextIcon.png This game has hidden development-related text.
GraphicsIcon.png This game has unused graphics.
ItemsIcon.png This game has unused items.
TextIcon.png This game has unused text.
DebugIcon.png This game has debugging material.

PrereleaseIcon.png This game has a prerelease article

Tetris: The Grand Master follows on from Sega's 1988 Tetris, aiming to give expert players a new challenge, and spawned three sequels: Tetris: The Absolute: The Grand Master 2 PLUS, Tetris: The Grand Master 3 - Terror Instinct, and Tetris: The Grand Master ACE.


Read about prerelease information and/or media for this game.
Prerelease Info

Debug Mode

A debug mode is available, but it requires access to the service menu as well as a 6-button kick harness.

  • For MAME 0.225 and later: turn on "Enable Debug Inputs" under Machine Configuration, which will enable 6-button inputs for Players 1 and 2.
  • For MAME 0.224 and earlier: use Player 3's A/B/C buttons in place of Player 1's D/E/F buttons, and likewise for Player 4 and Player 2.

To activate it, enter the service menu and go to the Dot Cross Hatch screen, then enter the following button sequence as Player 1: B, B, E, D, C, B, C, B, C, C, A, B, A, E, E, A, F, B, B, E, D, C, B, C, B, C, C, A, B, A, E, E, A, F.

If done correctly, "PUB ON" will appear near the lower-left corner of the cross hatch screen. From here on, some debug features are available using the extra kick buttons for either player:

  • Press D to cycle the next piece between the various item blocks available in a 2P game.
  • Hold D to make the current piece always fall at the slowest speed, regardless of level (except in 20G mode), and also pause the in-game clock.
  • Hold E to instantly discard your current piece and get the next one.
  • Hold F when a piece locks to instantly clear the entire field.

In addition, two other debug features are available with the standard inputs:

  • Hold P1 Start and press the P1 Coin button to enter Field Edit mode (see below).
  • Press the service coin button to toggle freeze frame on/off. When freeze frame is enabled, the P1 Start button will also advance the game by a single frame.

If you don't want to have to enter the code every time you start the game, you can also change the byte at RAM address 801859A0 to 02, or add the following to your tgmj.xml cheats file in MAME:

  <cheat desc="Debug Mode">
    <script state="run">
    <script state="off">

Field Edit Mode

TGM1 field edit 1.pngTGM1 field edit 2.png

Entering this mode allows you to completely change every cell in the playfield, as well as the current and next pieces.

After activating it, the game will pause and display "FIELD EDIT" over the playfield. At this point, press E to begin editing. From here, you can move the cursor to any cell and use the following controls for editing:

  • Hold B to select a block type, then press/hold E to place it in the current cell or A to erase the current cell.
  • Hold F to edit the current piece or C to edit the next piece.
  • Press the P1 Coin button to switch between players 1 and 2 in a two-player game.

When you're done editing, press D to display the "FIELD EDIT" message again, then hold P1 Start and press the P1 Coin button again to return to the game.

Any lines you make while this mode is active will also be cleared immediately once you return to the game, allowing you to fill and clear up to an entire playfield's worth of lines at one time for massive score bonuses.

(Source: Original TCRF research)

Unused Vs. Mode Item

Leftover code is present for an additional type of Vs. Mode "attack" item. While the code is mostly still in working condition, there are no graphics associated with it, so obtaining it instead displays the graphic for Press Field along with the text for Death Block:

TGM1 roulette icon.png

Using the item causes "ROULETTE!!" to appear over the other player's field, along with a large square that rapidly cycles through the seven different piece colors. The roulette will stop automatically after a few seconds, but can also be stopped manually using any of the A/B/C buttons.

When the roulette stops, all blocks of the chosen color become temporarily "solid", and a 1-cell-sized ball will drop from the top center of the playfield. As it falls down, the ball destroys any blocks that it touches, except for the "solid" blocks which will deflect the ball to the left or right. Once the ball reaches a dead end, it disappears and the "solid" blocks return to normal.

For some reason, while the programming for this item still mostly works as intended, there is actually no code that stops the ball from falling once it reaches the bottom of the playfield; instead, it simply falls through the floor and keeps dropping forever, continuing to "erase" random parts of the game's memory and usually resulting in a crash several seconds later. It is possible to fix this behavior using MAME's cheat system, however.

Adding the below code to your tgmj.xml cheats file in MAME will re-enable the unused item, making it obtainable both normally as well as with the debug buttons. This code also fixes the memory corruption issue, which makes the item usable in-game without causing crashes or other errors:

  <cheat desc="Add Unused Vs Mode Item">
    <script state="run">
      <!-- try to fix memory corruption from the ball thing falling through the floor forever -->
      <action condition="maincpu.pb@801c42d1 == 13 and maincpu.pb@801c42d8 == 5 and maincpu.pw@801c42e2 == 1">
        maincpu.pb@801c42d8=63 <!-- if item is in effect and the ball is at the floor, end the item -->
    <script state="off">
(Source: Original TCRF research)

Unused Graphics


Tgm 21.png Tgm 22.png Tgm 23.png

A number of unused backgrounds, suggesting that the game used an electron microscopy theme at some point.


The background from Hokuto's stage in Street Fighter EX (also developed by Arika), presumably used as a placeholder.

(Source: StriderVM)

Winners Don't Use Drugs

This image appears in the attract mode when the region is changed to "USA". Since the game never left Japan, it goes unused:


Hidden Developer Credits

Licensed by Sony Computer Entertainment Inc.(SCEI)
Library Programs (c) 1993-1997 Sony Computer Entertainment Inc., All Rights Reserved.
$Id: backup.c,v 1.3 1996/08/20 11:16:23 hakama Exp $ : 	Copyright (C) by 1993, 1994 Sony Computer Entertainment Inc.
$Id: jama.c,v 1.3 1995/06/09 04:12:37 hakama Exp $ : 	Copyright (C) by 1993 - 1995 Sony Computer Entertainment Inc.

This game uses the PlayStation-based Sony ZN-2 arcade system board, so the ROM has several copyright strings from Sony.

Q1 SOUND DRIVER   Version  (C)1997,1998 ARIKA,CO.,Ltd   By M.kakehiko  All Rights Reserved

This one isn't, though. This is for the sound driver.

Unused Input Test

An alternate version of the input test screen exists in the ROM. Since the game runs on PlayStation-based hardware, this version of the screen is designed for ordinary PlayStation controllers, with the extra kick buttons (and the coin slots) mapped to some of the additional buttons on controllers 1 and 2, respectively.

Normal Unused
TGM1 input test normal.png TGM1 input test unused.png

A very similar test screen can be seen in Street Fighter EX Plus Alpha, which also originated on the same arcade platform. To exit, press the Start and Coin buttons at the same time.

Adding the following to your tgmj.xml cheats file in MAME will replace the service menu's normal input test with the unused version:

  <cheat desc="I/O Test (item 1 in test mode)">
    <script state="on">
    <script state="off">
(Source: Original TCRF research)

Other Unused Test Screens

Two other service menu screens still also exist, but attempting to insert them back into the menu no longer fully works as intended due to missing or unemulated hardware.

CD Audio Test

RESULT   :%2.2X

Some sound-related text that, ironically, is more detailed than the actual sound test included in the final game. This would have been used for testing CD-XA audio playback using a PlayStation's CD drive.

The code for this screen is loaded at RAM address 8002F850, but locks up without displaying any text on-screen, probably while attempting to interface with a missing CD drive.

Flash ROM Writer

6. R O M  W R I T E R
%s   %x
****  FLASH ROM WRITER V0.001  ****
TGM1 flash writer.png

An interface for a Flash ROM writer. This will attempt to erase and rewrite the game's main CPU program ROMs.

The code for this screen is loaded at RAM address 800303F0, but running it in MAME causes it to enter an infinite loop almost immediately while attempting to erase the flash memory (which MAME simply emulates as regular ROM instead).

(Source: Original TCRF research)

Unused Regions

While the game only ended up getting released in Japan, Arika put in some work in preparation for an international release. The game's region code can be found (and changed) at 0x7FFFF in atej_04.2h.

  • 00: Japan
  • 01: USA
  • 02: Asia
  • 03: Europe
  • 04: Hispanic
  • 05: Brazil
  • 06: Nigata
  • 07: Odawara

Changing the region to anything other than "Japan" will cause the otherwise-unused English tutorial text to appear. Changing the region to "USA" specifically will cause the otherwise-unused Winners Don't Use Drugs image to appear during Attract Mode. See below for further information on both!

(Source: sampson on the TCRF discord)

Unused Texts

Note: This game stores each line of text in reverse order in the ROM, so bottom lines of text appear earlier and top lines appear later in ROM. For the sake of readabilty, some of the unused text has been reordered.

Warning Screen

       U S A       
This game is for use in the United States 
of America and Canada only.               
Sales, export or operation outside these  
countries may be construed as copyright   
and trademark infringement and is strictly
Violators are subject to severe penalties 
and will be prosecuted to the full extent 
of the law.                               
      A S I A      
This game is for use in the south-east    
Asian countries only.                     
Violators are subject to severe penalties
      E U R O      
This game is for use in all countries      
excluding the Western Hemisphere countries,
Japan and south-east Asian countries.      
Sales, export or operation outside these   
countries may be construed as copyright    
  H I S P A N I C  
This game is for use in the Western Hemisphere
countries except the United States of America,
Canada, and the Federative Republic of Brazil.
Sales, export or operation outside these      
countries may be construed as copyright and   
trademark infringement and is strictly        
Violators are subject to severe penalties and 
will be prosecuted to the full extent of the  
    B R A Z I L    
This game is for use in the Federative    
Republic of Brazil only.                  
Sales, export or operation outside this   
country may be construed as copyright and 
trademark infringement and is strictly    

This game was released only in Japan, so these warning texts weren't used. Texts for USA and Hispanic are complete, but others are cutoff and these were probably intended to reuse other warning texts for the rest.

    N I G A T A    
   O D A W A R A   

The names of two Japanese prefectures that apparently had stricter regulations on videogame violence at the time. Street Fighter EX treated these two prefectures as a separate region with some content changed. Why a Tetris game would feel the need to change content for these regions, however, is unknown.

How to play

The Tetraminos are
moved horizontally
by the lever.

[The Tetraminos are]
rotated by the buttons.

You can drop the blocks
quickly by putting the
lever down. 

When an entire
horizontal line is
filled with blocks,
the line clears from
the screen.

If the stack of the
blocks reaches the top,
the game is over !

There is some time
before the Tetramino
becomes fixed.

The Tetramino can be
rotated before it
[becomes fixed.]

Hold the button to
rotate the Tetramino
before it starts falling.

If you can rotate
properly before the
Tetramino becomes
fixed, then it is
possible to put it
in a tight spot.

To fill tight spots,
use the combination
of the lever and
rotation buttons.

This game was only released in Japan, but there's English tutorial text in the ROM. Note that some lines are reused but the ROM contains only one instance of them. These lines are marked with [] in the above dump.

This translated text appears in the tutorial if you change the game's region code, as listed above.

Demo Leftovers

TGM1 pub ver 1.pngTGM1 pub ver 2.png

Some leftover functionality, possibly from a demo or location test version of the game, can be activated by changing the byte at 0x7FFFE in atej_04.2h. Setting bit 01 causes "PUB VER" to appear on the boot screen; setting bit 02 will make the title screen display some text underneath the logo; this text no longer exists in the ROM, though, so it just displays garbage instead.

(Source: Original TCRF research)