Minesweeper Flags, Chording and Controls

What a flag is for

A flag is a note to yourself: this covered cell is a mine. It changes nothing about the puzzle, and you can clear an area without placing a single one. What it gives you is memory, since you do not have to work the same mine out again, and a safety margin, since a marked cell is easy to steer around at speed.

In the diagrams on this page, grey squares are covered cells, ✱ marks a mine, ⚑ a flag, and ✓ a covered cell that is safe to open. Numbered and blank squares are already open, and every cell just outside a drawing is open and holds no mine.

A flag also helps the numbers next to it: each neighboring number has one fewer mine left to account for, which often exposes a safe cell. What the numbers mean walks through that counting.

In the Shared World you also see other pioneers' flags, drawn semi-transparent. They are a live view, not saved to the world, and another player may simply be mistaken, so treat them as a hint, never as proof.

When to flag and when to skip it

Every flag costs one extra action, so how many you place is a trade between speed and safety.

Flag the mine when

• You plan to chord a number that touches it. Chording counts flags on the board, not the mines you are holding in your head.
• A number needs several mines accounted for, such as a 3 or a 4 with a few covered neighbors left.
• You are about to move to another part of the map and want your reasoning to survive the trip back.

Skip the flag when

• No number you still need to read touches the mine. A mine sealed in by opened cells costs time to mark and tells you nothing new.
• You are on a touch screen and the long-press would take longer than the move the flag supports.

Fast players flag only what a chord or a hard number needs; careful players flag every certain mine. Either works, as long as you never flag a cell you are only guessing about.

A wrong flag costs more than a missing one, as the last section shows. For habits that speed up a whole area, see Minesweeper strategy.

Counting mines by hand

Classic Minesweeper shows a mine counter: the total number of mines minus the flags you have placed. It is most useful late in a board, when a counter at zero means every cell still covered is safe, provided every flag is correct.

Minesweeper Worlds Online is played on a map with no edges, so there is no single board whose mine total you could count down from. The game's own tips also say mine density varies with the terrain, so no standard share of mines can be assumed.

Count locally instead, with the same arithmetic the counter does. Take a number and subtract the flags touching it. What remains is how many mines are still hidden among its covered neighbors.

If the number left equals the number of covered neighbors, all of them are mines. If the number left is zero, every covered neighbor is safe, and that last case is exactly what chording uses.

Chording: opening a whole ring at once

Chording works on a number that already has as many flags around it as its value. The number is satisfied, so every other covered neighbor must be safe, and a chord opens all of them in one move instead of one at a time.

A chord does not check your flags; it trusts them completely. Before you chord, count the flags around the number and make sure the count equals the number exactly. If one flag is doubtful, open the neighbors by hand instead.

Flagging and chording in Minesweeper Worlds Online

With a mouse

• Left-click a covered cell to open it.
• Right-click a covered cell to place a flag. Right-click the flag again to remove it.
• You can also hold the left button on a covered cell for about a quarter to half a second. A quick click opens the cell, and a longer hold places the flag.
• Left-click a number to chord it.
• Use the mouse wheel or the zoom slider to zoom, and drag to move around the map.

On a touch screen

• Tap a covered cell to open it.
• Long-press a covered cell to place a flag. Long-press the flag to remove it.
• Tap a number to chord it.
• Pinch to zoom and drag to move around the map.

If you are marking many mines, use the mode button in the top bar to switch between Reveal mode and Flag mode. In Flag mode a tap places a flag, so you skip the long-press, and the game remembers your choice on that device.

The button appears only when you are zoomed in far enough to see individual cells. If a tap opens a cell when you meant to flag it, check the active mode first.

Mistakes with wrong flags

A wrong flag is a mine marker on a safe cell. It does no harm while it sits there, but every chord next to it depends on it.

Minesweeper Worlds Online spells out the outcome. When every flag around the number is correct, the remaining cells open at once. When any flag is misplaced, a hidden mine gets opened, the area explodes, and the area locks. Only that area locks, and the rest of the world stays as it is.

To get back in, restore the area with a free restore when one is available, or watch a short ad in the mobile apps. While an area is locked it also costs you 10 points in the rankings.

How to avoid wrong flags

• Flag only from certainty: a number whose covered neighbors must all be mines, or a cell that a neighboring number rules out as safe.
• Before chording, count the flags around the number. More flags than the number says means something is already wrong.
• If a chord opens something unexpected, stop and recheck the nearby flags.
• Keep guesses to single taps or clicks. A guess you flagged and later chorded on turns one risk into several.

If the board really leaves you no safe move, avoiding guesses in Minesweeper covers what to do. Many apparent dead ends are solved by the shapes in Minesweeper patterns.