From one star to two: what changes
Page 6 of How to Solve Star Battle Puzzles.
Two-star puzzles are the next step for anyone who solves one-star puzzles, including Queens and Meowdoku. Two Not Touch is a two-star Star Battle puzzle. The rules change in one way:
- Every row, every column and every region holds two stars. A 10×10 board holds 20 stars.
- No two stars touch, not even at a corner. That has not changed.
Almost everything you know from one star still works. You only have to count to two. This page shows what changes, on a real 10×10 two-star puzzle from the app.
What stays the same
Star neighbors is exactly the same. A star rules out the squares around it.
Star neighbors: Rule out the squares around this star.
What changes: stars left
In a one-star puzzle, a star finishes its row, its column and its region. In a two-star puzzle, it does not. Row 3 now holds one star, and it needs a second. Nothing is ruled out in row 3, apart from the squares around the star.
So Finished now means a line or region holds two stars. And Last squares counts the stars left, not "one star". A row with two stars left and two open squares has two Last squares. Both are stars.
Last squares: This row has one open square and one star left. That square must be a star.
The words of the hint are the same as in a one-star puzzle: "one open square and one star left". The count it uses is the stars the row still needs.
What changes: a region inside a line
This is the change that is easiest to miss. In a one-star puzzle, if all the open squares of a region are in one row, the row is finished by that region and the rest of the row gets dots.
In a two-star puzzle it depends on the count. Look at the region below.
Its second star must go in row 1. But row 1 needs two stars, and this region holds only one of them. The other star of row 1 can be anywhere. So you cannot rule out the rest of row 1.
The rule is: rule out the rest of the line only when the region's stars left are the same as the line's stars left. Here they are one and two, so nothing is ruled out. Count both before you place a dot.
New moves for two stars
All the moves from Part 1 of the guide still work. But two-star puzzles also need moves that one-star puzzles rarely use. The number after each move tells you how much it matters: the share of the app's 10×10 two-star puzzles whose hints use it. The higher the number, the sooner you will need the move, so learn those first.
- Tight squeeze: 77% with one group of open squares, and 90% with several groups.
- Squeezed pair: 95%.
- Only one fit: 64%.
- 2×2 blocks: 59%.
- Sub-regions: about 3%.
These pages are coming soon, in the order shown above.
If a two-star puzzle stops, When you're stuck lists the moves in the order to try them.
Practice on puzzles like these in our Star Battle Puzzles app, for iPhone, iPad, Mac and Android.
Next: When you're stuck
Previous: Crowding
All parts of the guide