Tetris

Section 1: Introduction

Tetris is a falling-block puzzle game created by Alexey Pajitnov in 1984. Seven piece shapes — tetrominoes — fall into a rectangular well, and the player rotates and positions each one to complete horizontal lines, which then clear.

Modern licensed versions follow the Tetris Guideline, a standard maintained by The Tetris Company covering piece colours, the rotation system, randomisation and scoring. There is no independent governing body — the standard is the licensor's — so this is a community entry.

Note that older versions predate the Guideline and differ materially: the NES version used a different rotation system and no hold or ghost piece, which is why classic-era play looks so different from modern play.

Section 2: Platform & Setup

• Playfield: a well conventionally 10 cells wide and 20 or more visible rows tall.
• Seven tetrominoes: I, O, T, S, Z, J and L, each four cells.
• Controls: move left and right, soft drop, hard drop, rotate clockwise and anticlockwise, and hold.
• Under the Guideline, pieces are drawn from a 7-bag randomiser: each set of seven contains every piece once, so a long drought of a given piece is impossible.
• Guideline versions show a ghost piece marking where the current piece will land, and a hold slot to set one piece aside.

Section 3: Objective

Complete horizontal lines to clear them and keep the stack from reaching the top of the well. Tetris has no win condition in its endless form — play continues until the stack tops out, so the objective is to maximise score and survive rising speed.

• A line clears when all ten cells in a row are filled.
• Clearing lines lowers everything above them.
• The game ends when a new piece cannot be placed — a top out.

Section 4: Gameplay & Modes

Core Loop

• A piece spawns at the top and falls at the current gravity speed.
• Move and rotate it; a soft drop speeds descent, a hard drop places it instantly.
• Once it lands and locks, any completed lines clear and the next piece spawns.
• Gravity increases with level, and at the highest levels pieces lock almost immediately.

Rotation and Kicks

The Guideline defines the Super Rotation System, in which a rotation blocked by a wall or the stack is retried at offset positions — a wall kick. This is what makes T-spins possible and is the clearest single difference from classic-era versions.

Common Modes

• Marathon / endless: play until top out.
• Sprint: clear 40 lines as fast as possible.
• Ultra: maximise score in a fixed time.
• Versus: line clears send garbage rows to an opponent.

Section 5: Scoring & Winning

Scoring rewards clearing more lines at once. Under the Guideline, a single clear scores least per line and a four-line clear — a "Tetris" — scores most, with values multiplied by the current level.

• Single, double, triple, Tetris: increasing value per line cleared simultaneously.
• T-spin: rotating a T piece into a gap it could not otherwise reach scores substantially more than the same number of lines cleared normally.
• Back-to-back: consecutive Tetrises or T-spins, with no ordinary clear between, earn a bonus.
• Combo: clearing lines on consecutive pieces.
• Hard drop awards a small bonus per cell dropped.

In sprint modes the metric is time rather than score, and in versus modes it is lines sent.

Section 6: Competitive Rules

There is no sanctioning federation. Competitive play is organised by event, and the rules that matter are the ones each event fixes:

• Which version: classic NES play and Guideline-era play are effectively different games. Events specify the exact build.
• Randomiser: the 7-bag is standard under the Guideline; classic versions use a different, less forgiving randomiser.
• Rollover and kill screens: classic-era competition contends with the score counter and level behaviour breaking down at high levels, which is part of the challenge rather than a bug to patch.
• Input method: controller and technique restrictions (such as hypertapping or rolling) are set per event.
• The Classic Tetris World Championship is the best known event, but it is an independent competition, not a governing body.