The Super Rotation System, Explained

Four defined states per piece and a table of fallback offsets, which is what lets a piece spin into a gap it should not fit.

The Super Rotation System, usually shortened to SRS, is the rotation standard modern stackers implement. It replaced a decade of incompatible per-game rotation behaviour and, more importantly, made spinning pieces into tight gaps a reliable technique rather than a lucky accident.

Four states

Each piece has exactly four rotation states: spawn, right, flipped, left. Rotating clockwise advances one; counter-clockwise goes back one. The states are defined as explicit cell positions within a bounding box rather than computed from a rotation formula, which is why pieces do not drift the way naive implementations make them drift.

The O piece is the exception that proves the rule: it occupies the same cells in all four states, so rotating it does nothing at all.

When rotation is blocked

Here is the part that matters. If the target rotation would overlap the stack or a wall, a naive implementation refuses. SRS instead tries a short, ordered list of offsets — nudge left, nudge right, nudge up, nudge diagonally — and accepts the first one that fits. If none fits, the rotation fails.

That list is the kick table, and it is defined per piece type and per transition. The I piece has its own table because it is four cells long and behaves differently against walls.

Why the tables are the interesting part

Because they are deterministic and documented, players can build placements that depend on a specific kick. You set up a gap that a piece cannot reach by sliding, position it alongside, and rotate: the kick pushes it into the slot.

This is exactly how T-spins work, and it is why they became the centre of high-level play rather than a novelty. The behaviour is not luck; it is a lookup table you can memorise.

The side effects

Kicks are permissive, and that has consequences that were not entirely intended. Some rotations can push a piece upward, or into positions that look physically impossible. Purists find certain SRS placements ugly. The trade was accepted because expressive, learnable rotation turned out to be worth more than physical plausibility.

TETERI implements the standard tables, including the separate I-piece table, so setups learned elsewhere behave the way your hands expect.

Read next

• Wall Kicks: Why Your Piece Moved When You Rotated ItA blocked rotation tries a list of nudges before giving up. Knowing that list turns a quirk into a tool.
• Lock Delay: The Half-Second That Saves Your RunA landed piece does not lock immediately, and nudging it restarts the clock, up to a limit.
• The Ghost Piece and Why It Is Not CheatingThe outline showing where a piece will land removes arithmetic, not difficulty.
• How the Hold Slot WorksPark one piece for later, but only once per piece, which is what makes it a decision rather than an undo button.
• Counting the Bag: Knowing What Is ComingThe randomiser guarantees each shape once per seven, which makes the unseen pieces deducible rather than merely probable.
• Two Players, One KeyboardSplit-screen has a texture online play cannot reproduce, and a couple of practical quirks.