# Region Minesweeper

Region Minesweeper Example

Region Minesweeper is a puzzle original to this blog to the best of my knowledge. It combines the elements of Star Battle and Minesweeper.

Cell types

First, the grid is divided into several regions.

The cells are divided into four types. An unknown cell, represented with a white cell, must be eventually determined whether it’s a safe space or a landmine space. A radar cell, represented by a numbered cell, is known to have no mine below it. Moreover, it tells how many of the surrounding eight cells are mines. A blank cell or a safe cell, represented by a cell containing a cross, is known to have no mine below them, but it’s not occupied by a radar so that the number of mines around it is unknown. A mine cell, represented by a cell containing a nuclear symbol, is known to be a mine.

Interaction

As said above, a radar cell determines the number of landmines in the eight cells surrounding it. Moreover, each row, column, and region has the same number of mines, which is determined by the puzzle.

Objective

Determine whether each unknown cell is safe or has a mine.

Walkthrough

To get the most of the rules in a single puzzle, let’s try to crack them in the hard way.

Note that R1C1 and R2C1 only contain one mine, since their region has one mine identified already. So, to complete the column, R4C1 must be a mine.

Note that R4C2 and R4C3 contain one mine, so R4C4 is safe. This makes R1C4 and R3C4 to be mines.

See R2C4. Since it’s 3, then one and only one of R1C3 and R2C3 is a mine. So R4C3 is mine and R4C2 is safe.

Note R3C2. By the third row, this must be a mine. This makes R1C2 to be safe, and thus R1C3 to be a mine.

Note the 4. It’s full already, so R2C3 must be safe. The rest is very simple.