Spawn Location

A tetromino's spawn location is the place where it enters the playfield. The specific locations vary across different rotation systems, although they share the common characteristic of being between rows 20-24 and columns 4-7. Tetris guideline games in particular have two invisible rows above row 20 where the active tetromino spawns.

Left-handed vs. right-handed
L, J, T, S and Z pieces rotate in a 3x3 box and spawn horizontally in most games. There's no unambiguous way to spawn a 3 columns-wide piece in a 10 columns-wide matrix because it will always be off-center. The game designers must decide between these 2 choices:


 * left-handed: 3 empty columns on left side, 4 empty columns on right side
 * right-handed: 4 empty columns on left side, 3 empty columns on right side

The very first Tetris games (Electronika, IBM PC or the versions by Mirrorsoft) used right-handed. Nowadays, left-handed is the standard (e.g. see SRS). Some Tetris games used left-handed and right-handed simultaneously (e.g. Microsoft Entertainment Pack). There are cases where companies went for left-handed and right-handed in different games:


 * Nintendo: GameBoy Tetris and Tetris DX are left-handed; NES Tetris and SNES Tetris are right-handed
 * Spectrum Holobyte: The versions from 1987 and 1988 (e.g. PC or Macintosh) are left-handed; Super Tetris and Tetris Classic are right-handed
 * Gewaltig Entertainment: Cultris is right-handed; Cultris II is left-handed

On the other hand, I and O pieces can be centered in a 10 columns-wide matrix. Still, they are not centered in every game. For example, in Tetris (PC, Spectrum HoloByte) the O piece spawns one column more to the left, or in Tetris (Sinclair Spectrum) the I piece spawns one column more to the right.

Spawn locations in more recent guideline games
In the more recent guideline games such as Tetris Friends, the game first tries to spawn tetrominos in rows 20-21. If it fails then the game tries rows 21-22 like in older guideline games. If both attempts fail then the game ends.

For example, in this playfield all pieces except I spawn in rows 20-21 (shown in the outline), but I spawns in rows 21-22 (outside of the screen):