The usual advice for opening a Minesweeper board is that the first click is free โ click anywhere, the game moves the mine out of the way, and you get a safe start. That advice is wrong here. The version of Minesweeper on this site places every mine before you touch the grid, and it never relocates one. Your first click can end the game on the first second.
That changes how the opening should be played, and it opens a specific exploit that works on every board this game generates. This page covers both, then works through how far pure logic can take you before a guess becomes unavoidable.
There is no first-click protection
Starting a new game in Minesweeper runs the mine placement immediately: the board is built, mines are scattered at random across it, and the neighbour counts are computed โ all before any input. Nothing in the click handler checks whether the tile you picked is the first one. If you land on a mine, it detonates.
So a blind opening click is a straight gamble, and the odds are fixed by the difficulty you chose:
| Board | Grid | Mines | Chance a blind first click is a mine |
|---|---|---|---|
| Default | 10 × 10 (100) | 10 | 10.0% |
| Beginner | 9 × 9 (81) | 10 | 12.3% |
| Intermediate | 16 × 16 (256) | 30 | 11.7% |
| Expert | 16 rows × 30 columns (480) | 99 | 20.6% |
One expert game in five is lost before it starts, if you open at random. That is a real cost, and it is avoidable.
The bottom-right square is never a mine
The mine placer builds a list of every square on the board, then repeatedly draws a random entry from that list and removes it. The draw picks an index using the list length minus one โ which means the final entry in the list can never be selected while any other entry remains. Because the list is built row by row, left to right, that final entry is always the same square: the bottom-right corner.
The square is therefore never removed from the list, never marked as a mine, and is guaranteed safe on every board the game generates. This holds for all four presets and for any custom board where you ask for fewer mines than there are squares.
Two hundred thousand simulated placements per difficulty, run against the game's own placement routine, confirm it: the bottom-right square was chosen zero times on the default, beginner and expert layouts, while every other square landed within a percent or two of its expected share.
This is an artefact of how the shuffle was written, not a designed feature, and it is worth being clear about that. It also means the corner tells you nothing about the rest of the board โ the other squares are distributed evenly, so knowing one square is safe does not shift the odds anywhere else. What it buys you is a free opening click in Minesweeper, which on the expert layout is worth roughly one game in five.
The practical opening is therefore:
- Open on the bottom-right corner. It cannot kill you.
- If it reveals a blank, the flood-fill cascades and you may get a large opening for nothing.
- If it reveals a number, you still have a live board and a corner constraint โ a corner touches only three squares, so it is the most informative number on the grid.
A corner opening is the strongest one available even without the exploit, because corner and edge tiles have fewer neighbours and therefore constrain more tightly. The guarantee just removes the downside.
What a zero is actually worth
Clicking a square with no adjacent mines triggers a depth-first flood that clears every connected zero and the numbered ring around the whole region. A single lucky zero can open a quarter of the board.
The ring is the valuable part. Every numbered tile the flood exposes is a fresh constraint on the frontier, and constraints are what let you keep clicking without gambling. A zero that opens forty squares in Minesweeper typically hands you a dozen numbers, and those numbers usually cascade into another twenty forced moves before anything gets hard.
This is why opening moves should aim at space, not at safety alone once the first click is behind you. A click in a wide untouched region has a better chance of landing on a zero than one wedged against an established frontier, because zeros need all eight neighbours clear and that is likelier away from known mines.
The trade-off is real: opening new territory risks a mine, while working the frontier is often forced but yields one tile at a time. The right habit is to exhaust every forced move before spending a guess on new ground.
Exhaust the forced moves first
A guess is only justified when nothing on the board is deducible. In practice players guess far earlier than that, because they stop scanning too soon. The full sweep costs less than it looks:
- Any number whose hidden neighbours equal its outstanding mine count โ flag them all.
- Any number whose mines are all flagged โ every remaining hidden neighbour is safe.
- Any two overlapping numbers โ subtract the shared region and see what the difference forces.
Those three tests, applied until a full pass produces nothing, resolve most of a board. The named shapes โ 1-1, 1-2-1, 1-2-2-1 and the edge cases โ are shortcuts for spotting the third test quickly, and they are worked through in the Minesweeper patterns guide.
When you must guess, guess well
Some boards are genuinely unsolvable without a coin flip. When you reach one, three things improve the odds:
Count the remaining mines against the remaining hidden squares. The counter at the top shows how many flags you have left to place. If eight mines remain among twelve hidden squares, every unconstrained guess is a two-in-three loss and you should look much harder for a constrained one.
Prefer a constrained tile over an open one โ usually. A hidden tile touching several numbers has a probability you can actually compute from those numbers. An isolated tile in open space carries the global density instead. If the local probability beats the global one, take the local tile.
Prefer the corner and edge when the odds tie. Fewer neighbours means fewer ways for the guess to go wrong later, and a correct edge guess tends to open more forced moves than a correct middle guess.
Flags do not win the game
One habit worth breaking: you do not need to flag anything to win. The victory check scans for any square still in the untouched state, and mines never enter that state at all โ they are marked as mines when the board is generated. Clearing every safe square wins the game whether or not a single flag is on the board.
Flags remain useful, because they protect against misclicks and because they are what makes the double-click shortcut safe. But time spent flagging squares you have already reasoned out is time that does not advance the win condition. On timed runs, flag only what you need to.
The double-click shortcut is worth understanding properly before you rely on it โ in this version it clears a neighbourhood when every adjacent mine is flagged, and ends the game immediately when one is not. That behaviour and how to use it safely are covered in Minesweeper chording and flags.
A repeatable opening
Putting it together, an opening that never loses on move one and maximises what you learn:
- Click the bottom-right corner. It is guaranteed safe.
- If a region opened, work its frontier with the two forced-move tests until nothing fires.
- Apply subtraction across overlapping numbers, then the named patterns.
- Only now open new ground, choosing the widest untouched region.
- Repeat from step 2.
Run that loop on the default 10×10 board until it is automatic, then move up. The expert layout is not harder logically โ it is the same two rules โ but at 20.6% density it forces more guesses, so the discipline of exhausting forced moves matters more there than anywhere else.
When you want a break from probability, the same deduction muscles work on Sokoban and Nonogram, and the wider shelf is in the best puzzle games. Otherwise, open Minesweeper and start in the corner.