Board Generator

Click cells to place mines. Share the board hash or open it as a Mosaic puzzle.

๐Ÿ’ฃ Mines 0
3BV โ€” Standard โ€”
3BV โ€” Cylinder โ€”
3BV โ€” Toroid โ€”
Board Hash (place mines to generate)

Click a cell to place or remove a mine. Change the grid size and click Apply Size to reset the board.

Minesweeper Board Generator โ€” Design and Share Custom Boards

The Board Generator lets you place mines exactly where you want them on a custom grid, then produces a board hash โ€” a compact identifier that encodes the complete mine layout. Anyone with that hash can replay the exact same board in Standard, Cylinder, or Toroid mode. Use it to design challenges for friends, study specific configurations, or create Mosaic puzzles from a hand-crafted mine pattern.

What Is a Board Hash?

A board hash is a deterministic fingerprint of a mine layout. Given the same grid dimensions and the same mine positions, the hash is always identical โ€” which means a hash plus dimensions is everything needed to reconstruct the board exactly.

The hash appears in replay URLs across the site. When you finish a game on any standard, cylinder, or toroid board, your score record links to a replay URL built from that hash. The Board Generator runs the same encoding in reverse: you build the layout visually, and the hash is computed live as you click.

3BV Across Topologies

3BV (Bechtel's Board Benchmark Value) is the minimum number of left-clicks needed to clear a board without flagging. It measures board complexity โ€” a higher 3BV means more isolated numbered cells and fewer opening cascades.

The generator computes 3BV for all three topologies simultaneously:

  • Standard โ€” Flat grid. Border cells have fewer neighbours, so edge mines create more isolated numbered cells.
  • Cylinder โ€” Left and right edges connect. Edge cells now have a full 8 neighbours, which can merge cascades and lower 3BV.
  • Toroid โ€” All four edges connect. Every cell has exactly 8 neighbours. Typically the lowest 3BV of the three, since no cell is ever isolated by a border.

Mosaic Puzzle Design

Mosaic is a variant where every clue counts mines in a 3ร—3 area centred on the cell rather than in the 8 directly adjacent cells. Once you have a mine layout, the Mosaic section of the generator shows the corresponding number for every cell under Standard topology.

Click cells in the mask grid to hide their numbers โ€” those cells appear blank to the solver, making the puzzle harder. A masked Mosaic link encodes both the mine layout and the hidden-cell pattern, so whoever opens the link gets the exact puzzle you designed. Use this to craft puzzles with a clean logical path: hide only the cells whose values can be deduced from their visible neighbours.

Use Cases

  • Challenges. Design a specific layout, share the replay link, and compare times with friends on an identical board.
  • Analysis. Explore how changing mine positions affects 3BV across topologies. Moving a mine from a corner to an interior cell often drops 3BV noticeably.
  • Puzzle creation. Build a Mosaic puzzle with a known solution path โ€” place mines to produce a set of unambiguous clues, then mask any redundant numbers.
  • Practice boards. Create a layout that isolates a specific pattern (1-2-1, corner trap, mine chain) and replay it until the recognition is automatic.