Mine Sweep guide
A guide to Mine Sweep on OverTime: the three boards, desktop and phone controls, safe openings, reading patterns, common slips and how times rank.
How to play Mine Sweep
- 3 board sizes
- Fastest clear wins
Goal
Clear every square that does not hide a mine.
How to play
- Reveal a square to expose a mine, a blank, or a number.
- A number is how many mines touch that square across all eight neighbours, diagonals included.
- Flag the squares you believe are mines so you cannot open them by accident.
- Blank squares cascade, opening their neighbours automatically.
Reading the numbers
Two checks solve most boards. If a number already has that many flags around it, every other neighbour is safe. If a number equals its count of unopened neighbours, all of them are mines. Comparing two adjacent numbers resolves most of what is left.
Scoring
- Your time is the score, so a faster clear ranks higher.
- Hitting a mine ends the attempt.
Before your first board
Mine Sweep has three boards, chosen on the menu before you start. Easy is 9 by 9 with 10 mines. Intermediate is 16 by 16 with 40 mines. Expert is 30 squares wide and 16 tall, with 99 mines.
A bar above the board shows the mines left to find, the clock and the difficulty. The mine count drops with each flag and turns red if you place too many. The gear beside the difficulty opens the settings.
On a computer, left-click reveals a square and right-click flags it. Clicking a revealed number, or middle-clicking it, opens the rest of its neighbours once its flags are in place. On the keyboard, the arrow keys move around the board, Space or Enter reveals, and F flags.
On a phone, a Dig and Flag switch sits under the board. Holding a square for half a second also flags it, and that gesture can be turned off in the settings along with the sound.
- Number colours: Classic, Monochrome, or a vivid high-contrast Neon set.
- Question marks: a third mark in the flag cycle for squares you are unsure of.
- No-guess boards: every board can be cleared by logic alone, though it takes longer to prepare.
A sound way to start
Your first reveal is always safe. The mines are laid only after that click. None is placed on that square or its eight neighbours, so the first click always opens a patch.
The clock starts with that first reveal, not when the board appears. Because the opening is guaranteed, there is nothing to gain from hunting for a lucky first square.
When you are signed in, the server issues each board, and a brief Preparing your board notice can appear after your first click. If it takes longer than three seconds, you play a local board. A notice warns that this game will not count towards your stats or the leaderboards.
Work outwards from the rim of the opening. Its numbers hold all the information you have, and each square you solve adds more.
Reading the board as it opens
The rules give the two basic checks. Beyond them, a few shapes along a straight edge turn up on almost every board and are worth learning by sight.
Take a row of numbers beside a straight line of unopened squares. Reading 1, 2, 1, it has mines facing each 1, and the square facing the 2 is safe. A row reading 1, 2, 2, 1 has mines facing both 2s and none facing the 1s.
Chording saves clicks once a number is satisfied. When it has exactly that many flags around it, clicking the number opens every other neighbour in one move.
Near the end, check the mine counter. When only one or two mines remain, the total can settle a corner that the local numbers cannot.
After a win, the breakdown compares your clicks with the board's 3BV, the fewest clicks it can be cleared in. Efficiency near 100 per cent means very few wasted clicks.
Mistakes that end runs
Most lost boards come from a handful of habits rather than bad luck.
- Trusting a wrong flag. A chord opens every unflagged neighbour, so one misplaced flag sends it straight into a mine.
- Tapping in the wrong mode. On a phone, check the Dig and Flag switch first, because a tap meant as a flag in Dig mode opens the square.
- Guessing too early. Before taking a coin toss, scan the whole board for a safe square you have not yet solved.
- Flagging everything. Each flag costs time, so place one only where a chord will use it or where a misclick is likely.
Times, tiers and leaderboards
Each difficulty keeps its own leaderboard, so an Easy time never competes with an Expert one. You can also compare your times with your friends.
A lost board still counts as a game played, but it never reaches a leaderboard or replaces your best time. When you are signed in, the server replays your moves on the board it issued before it records the result. A guest's games are kept on that device only.
Every win earns a tier label. On Easy, ten seconds or less is Legendary, and anything slower than five minutes is Beginner. On Expert, Legendary needs a clear in two minutes or less.
The breakdown also shows a points score built from 3BV, efficiency and speed, with a bonus for clearing a no-guess board. A chart of your recent times sits beneath it.
Where to go next
If you like reaching certainty through elimination, try the daily Sudoku. It rewards the same patient checking, one square at a time.
Naval Strike turns deduction into a duel. Every miss narrows where your opponent's hidden fleet can be, much as every number narrows where the mines are.