Crowding
Page 5 of How to Solve Star Battle Puzzles.
Crowding is a "what if" move. Pick an open square and suppose that it holds a star. Follow what that star rules out. If it leaves a row, a column or a region with too few open squares for its stars, the supposition is wrong. The square gets a dot.
This is the move for hard one-star puzzles. In the app's hints, 42% of 8×8 and 63% of 10×10 one-star puzzles use it. In 8% of 8×8 puzzles there is a step where nothing easier applies, and Crowding does.
One example
This 8×8 puzzle opens with four Crowding hints, before any star is placed. Here is the third.
Crowding: A star in this square would finish its row and its column. That rules out the rest of both and the squares around the star. Then this region has too few open squares for its stars left. Rule out this square.
Suppose that row 6, column 3 holds a star. Then:
- Star neighbors. The squares around the star get dots. That takes away three squares of the region beside it: row 5, columns 3 and 4, and row 6, column 4.
- Finished. The star finishes row 6. The last square of the region, at row 6, column 5, is in row 6, so it gets a dot too.
- The region has no square left. All its open squares are ruled out, and it still needs a star.
That cannot happen in a solved puzzle. So row 6, column 3 cannot hold a star.
Why the app names it Crowding
Crowding uses the same steps that you know already. Place a star in your head, then do Star neighbors and Finished. The new step is to look at the other regions. Does any region have no open square left?
The hint tells you about the case where the star finishes its row, its column or both, as it did here. Crowding also covers a star whose neighbors alone leave a region with too few squares.
What to look for
- A region of three to five squares, close to another region. The squares of the small region are the targets.
- A square that touches several squares of that region. A star in it takes those squares away at once.
- A square in a row or column that is almost finished. A star there finishes the line and takes the rest of it away.
Try the square in your head. Do the Star neighbors and Finished steps, then count each region's open squares. If one is at zero, rule the square out.
Practice on puzzles like these in our Star Battle Puzzles app, for iPhone, iPad, Mac and Android.
Next: From one star to two
Previous: Every option agrees
All parts of the guide