Tetris: The Grand Master

Tetris: The Grand Master (テトリス ザ・グランドマスター) is a series of puzzle games created by Arika based on the popular Tetris license. The Grand Master series introduced several play mechanics to Tetris gameplay which can be seen today in its sequels and many other Tetris implementations.

The original game was followed by two sequels also developed by Arika: Tetris the Absolute: The Grand Master 2 in 2000 (with a Plus version released soon after) and Tetris: The Grand Master 3 - Terror-Instinct in 2005. A related console game, Tetris: The Grand Master Ace was published by AQ Interactive on December 10, 2005 and was a launch title for the Xbox 360's Japan release.

Gameplay
The basic gameplay of Tetris: The Grand Master (TGM) is similar to that of other Tetris games. The player must move and rotate Tetromino-shaped pieces falling into a well to form horizontal lines, which will then be cleared. During gameplay, the game automatically gives ranks to the player according to his/her score, starting from 9 all the way up to GM (Grand Master), roughly following the dan ranking system.

Levels
In most Tetris games, the game level (signifying its difficulty) will increase by one every time the player clears 10 lines. A different system is used in TGM however. Levels in TGM increase by one for every piece that is spawned and for every line cleared (except in TGM 3: Terror-Instinct (TI), where 4 levels are awarded for a triple and 6 levels for a tetris). The exception to the rule is when the lower two digits of the level is at 99 (99, 199, 299, etc.) and on level 998. When in this state (referred to as "level stop"), the level can only be increased by clearing lines, and not by placing pieces.

The player clears the game by reaching the final level of the mode. TGM 2: The Absolute Plus' (TAP) Versus mode has a default ending of level 200 (and a time limit of 2:40.00), but is rarely ever reached in typical play. In TAP ' s Normal and Doubles modes, the game ends at level 300 (Doubles ends when both players have reached 300). In every single other mode besides TI's Shirase mode (TA ' s Master; TAP ' s Master, TGM+, T.A. Death; TI ' s Master), the game ends at level 999. TI ' s Shirase mode ends at 1300, and TI ' s Sakura mode ends after the 20 default stages. As well, all modes (besides Versus and Sakura) have a playable credit roll after the end of standard play, which is required for some of the highest ranks in the game, and Sakura has 7 extra stages that can be challenged if the player clears the 20 normal stages without failing within less than 5 minutes.

The ultimate goal of the game is to achieve the highest ranks of Grandmaster (or S13 in Shirase), by completing various requirements that take various levels of skill, ranging to fairly simple in TGM to world class skill in TI. As well, many players challenge themselves with time attacks in each mode, aiming to achieve Grandmaster (or S13) in the shortest amount of time.

Speed
The fall speed is measured in units called G, or grid cells per frame. The game internally tracks the gravity (referred to as "internal gravity"); dividing this number by 256 will result in the fall speed. In TAP Master mode, the internal gravity follows the following table:

After reaching level 500, the falling pieces cease to have an airborne phase and instead will instantly appear at the top of the stack. This state is referred to by developers of the game as 20G. Previously, players would align the horizontal position while the piece is still airborne and then drop the pieces, but this becomes impossible since the pieces are already at their lowest possible vertical positions when they appear. Instead players are required to quickly trundle the pieces along the terrain to get them to their intended locations before they lock down. Similar conditions can be observed in some modern iterations of Tetris such as level 20 of Tetris DS. However, TGM's rotation system makes it much more difficult to play during 20G, compared to Tetris DS.

Starting after TGM, Arika also uses a variety of other factors to speed up the play, besides solely gravity:
 * 'Lock delay' refers to the length of time from when a piece touches the top of the stack until it is forcibly locked in place. This delay can be skipped by pressing down on the joystick.
 * 'Line clear delay' refers to the length of time it takes for the game to play the animation of a line clearing.
 * 'DAS' (delayed auto-shift) is the length of time from which the player can hold a horizontal direction on the joystick until the piece begins to "auto-shift", or move at a speed of 1G.
 * 'ARE' (from the Japanese あれ are, used to refer to an object that does not have a given name, a remnant of the days of Sega arcade Tetris, where Japanese players did not know what to call it) is the length of time from when the previous piece locks and the next piece spawns on the playfield. During this time, players may "charge" DAS inputs, or "pre-rotate" the piece using the Initial Rotation System. (As well, in TI, the player may hold the piece)
 * 'Line ARE' is the length of ARE after clearing a line. This time is the same as ARE in TGM.

In TGM, the timings are fixed for the entire game as follows:

However, in TA and TAP Master mode, the timings are shortened throughout the game in order to force and allow the player to play at much faster speeds.

TGM Rotation System
TGM's rotation system (sometimes called ARS for "Arika Rotation System") is a modified version of the classic Sega arcade Tetris rotation system, with a few added tweaks to make the game playable in 20G conditions.

TGM was the first Tetris game to pioneer the use of 'wallkicks', which occur when the player attempts to rotate a tetromino into a space it cannot occupy, either due to the walls of the playfield or due to the geometry of the already-locked pieces. In TGM, TA, and TAP, the game checks three locations whenever the player rotates to adjust the piece if necessary.
 * 1) Basic rotation
 * 2) Attempt to move the piece one space to the right
 * 3) Attempt to move the piece one space to the left

If either the last two occur, the piece will 'kick' off of the wall (or a locked piece) and will be able to rotate. If all three fail, the piece will not rotate. In addition, there are a few extra rules where the game will disallow the player to kick certain pieces:
 * The 'I' tetromino is not allowed to kick
 * 'L', 'J', and 'T' tetrominoes, from their 3-wide orientations, will not kick off their center column

TI changes a few mechanics to allow the player to effectively play at its much higher speeds:
 * The 'I' piece can now wallkick. It may either kick 1 or 2 spaces to the right, or 1 space to the left (called the "right-side bias")
 * The 'I' piece can now 'floorkick'. If its rotation is blocked, it can shift either 1 or 2 spaces upwards
 * This can only be done once per 'I' piece
 * The 'I' piece cannot floorkick while it is in mid-air
 * The 'T' piece can floorkick as well.
 * This can be done twice per 'T' piece

The directions of left and right are not reversed when playing in Reverse mode.

Temporary Landing System
As would later become part of the Tetris Guidelines, Arika also included the TLS, or Temporary Landing System, showing a "ghost piece" indicating where the current piece will fall on the stack if dropped. The TLS is removed after reaching level 100 in all applicable modes, however, an in-game code exists to allow it for the entire game.

Credit roll
In TGM, the credit roll is merely decorative, essentially a "victory lap" for the player. Nothing is awarded if the player survives the credits, and they can be sped up and skipped using the start button.

In TA and TAP Normal, TGM+, Doubles, and T.A. Death, the credit roll is merely decorative as it is in TGM. Normal mode's credit roll plays at a slow 20G, TGM+'s functions much like Master mode, T.A. Death continues the game's speed, and Doubles mode's plays at 20G. Master mode's normal credit roll has the pieces fade to invisible 5 seconds after they are locked (called the "fading roll"), and is also merely aesthetic.

In TA and TAP Master mode, if the player reaches the highest grade of S9 before the end of the game and fulfills a variety of other time and line clear requirements, the credit roll played will be the 'M'-Roll (or "invisible roll"). In this roll, the piece turn invisible as soon as they are locked. If the player does not survive the M-Roll, they will be awarded the grade of M. If the player manages to survive the entire credit roll, they will be given the grade of Grandmaster.

The 'fading roll' and 'invisible roll' challenge return in TI, but the requirements to reach them along with their function is vastly different. Instead of merely needing to survive the credit roll, the player is graded within credit rolls. In order to reach the rank of Grandmaster, the player must stack efficiently and clear many tetrises, in addition to surviving the breakneck speeds of the invisible roll. The highest rank ever achieved in a fading roll in TI is a MasterV.

For an extra challenge, TA and TAP also keep track of how many lines the player has cleared in the M-Roll. If the player manages to clear 32 lines during the M-Roll (and survive the roll), they will be given the Grandmaster grade as usual, but their score on the ranking screen will have an orange line under it, referred to as the Orange Line GM. Otherwise, the player will receive a Green Line GM. Orange Line GMs are always prioritized over Green Line GMs on the ranking screen, regardless of clear time. TI also gives Green/Orange Line S13 in Shirase mode. The player receives an Orange Line S13 if they manage to survive the credit roll, which is composed of a Big Mode challenge with the monochrome [] bracket blocks from levels 1000-1300 of normal play. If the player fails the credit roll, they receive a Green Line S13.

The game will continue to award secret grades, even within the credit roll, although most players have never attempted it, with even one of the best players in the world only being able to stack a T.A. Death Secret Grade 4 while in the credit roll.

Grades
Grades in the first TGM game range from 9 to 1, then count up from S1 to S9, and end with Grandmaster. In TGM, the grade is solely determined by the player's score (except for GM, where a few grade and time requirements can bar the player from receiving GM, regardless of score).

The GM Requirements are as follows:

TAP's Master mode adds a very grueling list of requirements in order to qualify for the M-Roll, including absolute and relative time requirements, as well as requiring a certain number of tetrises cleared in each section. Without the M-Roll, the highest grade achievable is an S9.

TI's Master mode keeps much of the same relative time requirements (the absolute requirements change due to the faster nature of the game), but removes the tetris requirements. Instead, the player must achieve a 'Section Cool' in each section aside from the last one, as well as have an internal grade of 27 (roughly an S7 in TAP). TI also adds a number of filler grades between S9 and GM:

TI's Shirase mode will award a player an S grade equivalent to the number of sections cleared. The player can lose grades if they take over 1:00.00 in a section, which will grant them a 'Section Regret!,' demoting their grade by 1.

In TAP's T.A. Death mode, if the player does not manage to reach level 500 within 3:25.00, the game will instantly end, the credit roll will play, and the player will not receive a grade. If the player manages to pass this time barrier (known as a "Torikan"), they will be awarded the M grade. The Grandmaster grade is awarded regardless of score or time at level 999.

TI's Master mode has a torikan as well, although it is nearly impossible to achieve in normal play: if the player reaches level 500 in Master mode in 7:00.00 or greater, the game will end with no credit roll (except during qualification exams, where it will continue to 999).

TI's Shirase mode has a particularly difficult torikan at level 500: if the player does not reach level 500 in 2:28.00 (Classic) or 3:03.00 (World), the game will end with no credit roll and the player will be awarded an S5 (if they have no received any 'Regret!' reductions). As well, there is a Torikan at level 1000, with a requirement of 4:56.00 (Classic) or 6:06.00 (World), however it is much harder to fail due to the natural pacing of the game. Ichiro Mihara, the creator of the series, has stated that level 1300 in and of itself is another torikan, however this theory have been debunked by reverse-engineering of the game's code and confirming that no grades beyond 1300 exist.

Grand Master
Grand Master is the highest rank in the main mode of each game. Hundreds of players are known to have a GM in TGM, with 113 known GMs in the west. The fastest known GM time attack is 8:48.60 by 777, however, the fastest recorded GM time attack is 8:49.90, also by 777.

In TAP Master mode, 8 Western players have achieved a GM grade (with 5 Orange Line GMs): KevinDDR, Kitaru, K, Qlex, ApertureGrills (TWF), cyberguile, MaryHadALittle, and DeHackEd. The fastest known GM time attack is an Orange Line 7:15.60 by SQR. The fastest known clear of Master mode is an Orange Line S8 7:12.55 by kashiwa0903.

In TAP T.A. Death mode, 16 Western players have achieved a Death GM grade: Qlex, batfly, K, Amnesia, Kitaru, COL, MaryHadALittle, colour_thief, rednefed, DeHackEd, Rosti LFC, KevinDDR, ApertureGrills (TWF), FeV, steadshot, and cyberguile. The best known T.A. Death time is 4:52.58 by kashiwa0903.

Only six players have achieved a Classic Master GM in Tetris: TGM3. The first player to achieve it is Japanese player 'jin8' on July 28th, 2007. The next four were also Japanese (known by their arcade names of KAN, DIS, SKH, and Kashiwa0903 (KFC)). The first foreign player to achieve the feat was American speedrunner Kevin Birrell (KevinDDR) on January 28, 2015. So far, only 4 other players in the west have achieved games of the next closest rank, MasterM: K, ApertureGrillz (TWF), nahucirujano, and Kitaru. As well, Kevin and another player known as [-Steve-] have achieved World Master GMs.

A handful of players have achieved Classic S13 in Shirase mode, with 4 (2 Orange Line S13) in the west: KevinDDR, nahucirujano, Altimor, and Amnesia. As well, 4 players have achieved World S13 (with 3 Orange Line S13): [-Steve-], farter, KevinDDR, and mat. The fastest known Classic Shirase S13 is an Orange Line 4:03.38 by ZAB, and the fastest known World Shirase S13 is an Orange Line 3:53.85 by hebomai.

Tetris: The Grand Master
The original game was released in Japanese arcades in August 1998.

Tetris the Absolute: The Grand Master 2
This entry was released in 2000, and added additional modes of play. One of these new modes is the Master mode, which extends the classic TGM gameplay with larger speed increases, more requirements to achieve the M or GM grades, and an additional challenge when the M rank is achieved where the player must survive the credits roll with the additional handicap of the Tetriminos turning invisible upon locking. Additional modes include a more casual Normal mode, a Versus mode enhanced with item battles, and a two-player co-op mode.

Tetris the Absolute: The Grand Master 2 Plus
The entry added additional modes such as TGM+, which adds rising garbage blocks to the gameplay, and T.A. Death where the game begins at 20G and every other aspect of the game also speeds up steadily.

Tetris with Cardcaptor Sakura Eternal Heart
This game uses the rotation system of The Grand Master, but emphasized in clearing jeweled blocks, similar to Sega's Flash Point game.

Tetris: The Grand Master 3 - Terror-Instinct
This game was released in 2005. The game now runs on PC-based hardware, specifically the Taito Type X. The level system has been expanded in many forms with increasingly stricter requirements to reach the Grand Master rank. Modes include Easy, Sakura (a puzzle mode), the traditional Master mode, and Shirase (an extension of T.A. Death with even harsher speed, garbage, and levels beyond 999). It also features World and Classic Rules, which the former was added by Arika due to The Tetris Company's recent policy changes.

The Grand Master 2015
In mid-2015, Arika began location testing of a new, fourth installment in the franchise in both Japan and the United States, simply titled The Grand Master 2015, dropping the Tetris license. The location test featured Rounds mode, similar to TGM3's Shirase with even harsher speeds and over 1300 levels; and Konoha, which features Tetrominoes twice as big (simulating a 5x10 field), and the objective is to clear the playfield of all pieces as many times as possible.

The overseas version of the game was announced to be tested at the third week of June 2015 under the title 'TGM3Ω'.

Tetris: The Grand Master 4 - The Masters of Round
In September 2009, Tetris: The Grand Master 4 - The Masters of Round was unveiled at the Amusement Machine Show. At least three modes of TGM4 have been shown so far: Master mode, Konoha mode (a mode in which all pieces are double size and the object is to completely clear the playing field of blocks as many times as possible), and Rounds mode (similar to T.A. Death and Shirase modes, but with more levels and a fog mechanic that prevents line clears below a particular height until certain conditions are met). Additionally, it featured World and Classic types just like Tetris: The Grand Master 3. TGM4 was supposed to run on the Sega RingWide hardware, however the game has since been cancelled.