# Starbattle – Logic tutorial for 1 star game variant

How the 1 star variant of the game works.

## Rules

There are 4 simple rules to solve the puzzles:

- All rows must contain 1 star.
- All columns must contain 1 star.
- All islands must contain 1 star.
- Stars may not be neighbors – not even diagonally.

To solve a puzzle one simply applies these rules *over and over*.

There’s only one valid solution to each puzzle, and by applying the rules logically you get there!

## Example:

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | ||||

2 | |||||

3 | |||||

4 | |||||

5 |

The island 5 (X 1, Y 1) only consists of 1 field. By the rules it needs exactly 1 star. So the position of that star in that island is obvious.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | |||

2 | • | • | |||

3 | |||||

4 | |||||

5 |

Since there may not be other stars next to a star, we can rule out the first stars’ neighbor fields. We do so by marking them with a dot here.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | |||

3 | • | ||||

4 | • | ||||

5 | • |

Since every row and column must contain only 1 single star, we can rule out that the first row/column contains stars anywhere else. We mark the empty fields with a dot.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | ||

3 | • | ||||

4 | • | ||||

5 | • |

The island 4 has only as many free fields as it lacks stars, so we can place them.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | |

3 | • | • | • | • | |

4 | • | ||||

5 | • |

Neighbor-Rule: next to a star can be no other star.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | • |

3 | • | • | • | • | |

4 | • | • | |||

5 | • | • |

We found all the stars in column 3, so we can now exclude the remaining empty fields.

We found all the stars in row 2, so we can now exclude the remaining empty fields.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | • |

3 | • | • | • | • | ★ |

4 | • | • | |||

5 | • | • |

The row 3 has only as many free fields as it lacks stars, so we can place them.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | • |

3 | • | • | • | • | ★ |

4 | • | • | • | • | |

5 | • | • |

Neighbor-Rule: next to a star can be no other star.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | • |

3 | • | • | • | • | ★ |

4 | • | • | • | • | |

5 | • | • | • |

We found all the stars in column 5, so we can now exclude the remaining empty fields.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | • |

3 | • | • | • | • | ★ |

4 | • | ★ | • | • | • |

5 | • | • | ★ | • |

The column 4 has only as many free fields as it lacks stars, so we can place them.

The row 4 has only as many free fields as it lacks stars, so we can place them.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | ★ | • | • | • | • |

2 | • | • | ★ | • | • |

3 | • | • | • | • | ★ |

4 | • | ★ | • | • | • |

5 | • | • | • | ★ | • |

Neighbor-Rule: next to a star can be no other star.