Lights Out Game: Rules, History and Strategy

Published 2026-10-22 · Nightlit

Lights Out is one of those puzzles that looks simple for about ten seconds. You get a grid of lights, you press one, and five of them change. Within a minute most people have made the board worse. This guide covers the rules, where the game came from, why it can always be solved, and the strategy that gets you from “random tapping” to “solved in par.”

The rules

The classic game is played on a 5x5 grid of lit buttons.

1. At the start, some lights are on and some are off.
2. Pressing a button toggles it (on becomes off, off becomes on).
3. The same press also toggles the buttons directly above, below, left and right of it. Diagonals are not affected.
4. Buttons on an edge have only three neighbours, and corners have two, so they change fewer lights.
5. You win when every light is off, ideally in as few presses as possible.

That’s the whole game. Modern versions sometimes flip the goal. In Nightlit, for example, the aim is to turn every tile gold rather than dark, but the move is identical, so the same strategy works.

Two properties make Lights Out unusual:

• Order doesn’t matter. Pressing A then B leaves the board exactly as pressing B then A does.
• Pressing twice undoes itself. A second press on the same button cancels the first.

Put together, a solution is just a set of buttons, each pressed once. That’s the key to everything below.

A short history

1978: Merlin. Parker Brothers’ handheld Merlin included a game called Magic Square on a 3x3 grid. It’s probably the first electronic game of this kind, though its buttons flipped different shapes from Lights Out’s plus sign. The goal was to light a ring around a dark centre.

1983: the XL-25. Vulcan Electronics released the XL-25, invented by Hungarian mathematician László Mérő according to puzzle historian Jaap Scherphuis. It played the standard plus-shaped game on a 5x5 grid (with the goal of turning all lights on) and a variant where each button flipped the squares a chess knight’s move away.

1995: Lights Out. Tiger Electronics (Tiger Toys) released Lights Out, the version that gave the puzzle its name. It was patented in the US in May 1995, and Wikipedia credits a team of six designers: Avi Olti, Gyora Benedek, Zvi Herman, Revital Blumberg, Avi Weiner and Michael Ganor. The handheld came with built-in puzzles, and Newsweek covered it that year under the headline “A New Toy That Teaches.”

1997 onward: the family grows. Tiger shipped Lights Out as the pack-in game with its Game.com handheld (1997), then released spin-offs:

• Lights Out 2000: lights cycle through three states (off, red, green) instead of two.
• Lights Out Cube: a 3x3x3 cube where presses wrap around the edges onto neighbouring faces.
• Lights Out Deluxe: a 6x6 grid, with an alternative diagonal “x” move.

Since then the puzzle has been rebuilt countless times as a browser game, a phone app and a coding exercise. It’s also a favourite in linear algebra classes, because the whole game can be written as a system of equations.

Sources: Wikipedia: Lights Out (game) and Jaap Scherphuis’s Lights Out page, the most thorough reference on the puzzle and its variants.

The math, in plain words

You don’t need math to play, but three facts explain why the game feels the way it does. We checked each by running every possible 5x5 board through a solver.

• Only 1 in 4 random boards can be solved. Of the 33,554,432 possible on/off patterns, exactly 8,388,608 are solvable. A well-made Lights Out game never shows you an impossible board, because it creates puzzles by scrambling a solved grid with presses.
• Every solvable board has exactly four solutions. That’s because the 5x5 grid has three “quiet patterns”: sets of presses that change nothing. Add one to any solution and you get another valid solution.
• No board needs more than 15 presses. Most need 9 to 12, and the most common shortest solution is 10 presses.

On a 6x6 board there are no quiet patterns, so every one of the 2^36 patterns is solvable and each has exactly one solution. Board size changes the character of the puzzle more than you’d expect.

Strategy: from beginner to par

Beginner: chase the lights

The universal method is called chasing the lights:

1. For each lit button in row 1, press the button directly below it in row 2. Row 1 is now dark.
2. Repeat for rows 2, 3 and 4. Now only row 5 can have lights left.
3. Look up the leftover bottom row in a short table, press the matching buttons in row 1, and chase down again.

Our Lights Out solver post has the full table, a worked example and an interactive solver. The step-by-step guide walks through the same method more slowly.

Intermediate: think in shapes

Once chasing feels automatic, start reading the board before you press:

• Plus signs. Five lights in a plus are one press in the centre.
• Edge Ts and corner Ls. Four lights in a T along an edge, or three in an L in a corner, are also one press.
• Side-by-side pairs. Two presses next to each other leave their own two tiles unchanged and flip the six tiles around them. Recognising that ring saves a lot of wasted moves.

Advanced: find the minimum

Chasing always works but rarely gives the shortest answer. To get there, take the set of presses that chasing gives you and combine it with each of the three quiet patterns (presses in both cancel out). One of the four results is the shortest solution. In Nightlit, that number is the board’s par, and matching it earns three stars.

Common mistakes

• Pressing lit buttons on purpose. It feels natural to press the lights you want gone, but a press affects five tiles. Press the tile that fixes the row above.
• Fixing the bottom first. Always work top-down; the bottom row is where the leftovers collect.
• Forgetting presses cancel. If your plan presses the same tile twice, drop both.
• Rushing the last row. When only the bottom row is left, stop and look it up instead of guessing.

Where to play Lights Out today

The original Tiger handhelds still turn up second-hand, and there are many free browser versions. If you’d like a daily take, Nightlit gives everyone the same 5x5 board each day, with a par to beat, a streak to keep and a share grid for friends. It’s free in your browser in English and Spanish. For more daily games in the same spirit, see our list of free daily puzzle games you can play in your browser.