Expert Minesweeper

Minesweeper is played on a grid of covered squares. Some of them hide mines; the rest are safe. The goal is to uncover every safe square without opening a mine.

Expert is a 30 by 16 grid with 99 mines, about one square in five. On a phone held upright the board turns on its side, so it fits the screen.

• Open a square to see what is under it. A mine ends the game.
• A safe square shows a number: how many of its eight neighbours (sideways and diagonally) hold a mine. A square with no mine around it opens its neighbours for you, so whole areas clear at once.
• Put a flag on a square you know is a mine. Flags are only notes for you; they don't count toward winning.
• The game is won when every square without a mine is open. The counter above the board shows the mines minus the flags you have placed.

With one square in five a mine, numbers are higher and open areas are smaller. Most random expert boards reach a point where no reasoning helps, and players have to guess. We only list boards our solver cleared from the start with sure steps, about one in seven of those it tried.

Some of those steps go beyond single numbers and pairs. Our solver also looks at a whole group of touching numbers and checks every way their mines could fit; a square that is safe in all of them is safe. Near the end it also counts the mines left.

When pairs run out, pick a short stretch of the border and try both choices for one covered square: if putting a mine there breaks a number somewhere, it is safe; if leaving it empty does, it is a mine. That is the same reasoning our solver uses, done by hand.

Watch the mine counter late in the game. If the numbers along the border need exactly as many mines as are left, every covered square away from the border is safe, even ones no number touches.

Click or tap a square to open it. Right-click, or press and hold on a phone, to put a flag on it or take it off. Flag mode below the board makes every tap a flag, which is easier on a small screen.

Tap a number whose mines are all flagged to open every other square around it at once (this is called chording). If one of your flags is wrong, that opens a mine, so flag with care.

Your first click is always safe. Each board starts at a cell marked with a gold ring: wherever you click first, that area opens, and from there the whole board can be solved by reasoning. Hint shows the next sure square and why; press it again to open or flag it. On a keyboard, the arrow keys move, Enter or Space opens, and F places a flag. Your game is saved in this browser.

Clear the easy squares first, all around the open area, then come back for the hard spots: every opened square adds numbers that may settle them.

If you are stuck, Hint marks the numbers that decide the next square and names the reason, from a single number up to the mine count. It is a good way to learn the patterns that make expert boards quick.