What is the no-touch rule in Star Battle?

The no-touch rule says no two stars may sit in cells that touch, including diagonally. Around every star all eight neighbouring cells must stay empty. It is the constraint that makes the puzzle work: each star you place rules its eight neighbours out, which is why marking those cells with excludes is the heart of solving.

How do you start a Star Battle puzzle?

Begin with the tightest region, row or column, the one where the required stars barely fit. Small or thin regions force their stars into a narrow set of cells, letting you exclude that star from the rest of the row or column. Each star you place excludes its eight touching cells, which tightens the neighbouring lines and regions so the grid opens up from its most cramped corner.

What is containment in Star Battle?

Containment is the key counting technique. If every cell a region could use for its star sits within one row or column, that region's star must lie in that line, so you can exclude the star from the rest of the line outside the region. In two-star puzzles you extend it: if two rows can only place their stars in two regions, those regions are full and their other cells are excluded.

Does solving Star Battle ever require guessing?

No. A well-made Star Battle has exactly one solution reachable by pure logic. Every Puzzle Lair Star Battle is generated and verified to be solvable without guessing, so being stuck means there is a deduction you have not spotted yet, often a containment or counting check you have not run. When you think you have placed every star, press Check to test the board. There is no mistake limit.

Solving guides

From the rulebook

How to Solve Star Battle

Star Battle, also known as Two Not Touch, is a logic puzzle played on a grid split into bold-outlined regions. You place a fixed number of stars in the grid so that every row, every column and every region holds the same count, and no two stars ever touch, not even diagonally. Those two rules pull against each other, and once you can read them together they give you plenty to work with. This guide takes you from the rules to the techniques that crack hard grids without guessing.

Play Star Battle

The rules of Star Battle

A Star Battle grid is divided into bold-outlined regions, one region for each row of the grid. Every puzzle has a star count, written as one star or two stars per unit. You must place exactly that many stars in each row, in each column and in each region. A one-star puzzle puts a single star in every row, column and region, while a two-star puzzle puts two in each.

The second rule is the no-touch rule, which gives the puzzle its bite. No two stars may sit in cells that touch, including diagonally. Around every star all eight neighbouring cells must stay empty. Together the equal-count rule and the no-touch rule are the whole game, and every deduction comes from playing one against the other.

Mark ruled-out cells with excludes

The single most useful habit is marking dead cells. Whenever a cell cannot hold a star, put an exclude mark on it. The moment you place a star, exclude all eight cells touching it, since the no-touch rule forbids stars there. Excluding cells is how you turn vague pressure into hard fact, and it makes the next deduction visible.

On Puzzle Lair the excludes are an optional aid, only the stars are required to finish, but they are how the puzzle is meant to be solved. Marks give no live feedback as you play, so when you think every star is placed, press Check to test the board. There is no mistake limit, so you can keep editing or clear the board and try again.

Start where the count meets the space

The fastest opening move is finding a row, column or region so tight that the stars are nearly forced. A small region only has so many cells that do not touch each other, so look for regions where the required stars barely fit. If a one-star region is a thin strip of cells in a single line, that whole line is spoken for and you can exclude the star from that row or column elsewhere.

Look too for lines that are almost full of excludes. When a row needs one star and every cell but one is already ruled out, that last cell takes the star. Each star you place fires off eight fresh excludes, which tightens the neighbouring lines and regions in turn, so the grid unravels from its most cramped corner outward.

Use region and line containment

The strongest Star Battle technique is containment, the equivalent of pointing pairs in Sudoku. If all the cells a region could use for its star sit inside a single row, then that region's star must lie in that row, so the row's star is accounted for and you can exclude it from the rest of that row outside the region. The same works for columns, and in reverse: if a row's stars can only fall inside one region, that region is full and its other cells are excluded.

Counting drives the hardest deductions. In a two-star puzzle, if two rows together can only place their stars within two regions, those two regions are entirely consumed by those rows, so every other cell in both regions is excluded. Comparing how many stars a block of rows needs against how many regions can hold them is how you break into the toughest grids.

Combine the no-touch rule with elimination

When the obvious moves run out, lean on the no-touch rule to eliminate. Two stars in adjacent columns of neighbouring rows would touch, so placing one star quietly forbids a diagonal band of cells. In a two-star row, the two stars need at least one empty cell between them, which limits how they can sit and often splits a line into separate zones.

Apply the techniques in order: exclude the cells around every star, solve the tightest regions and lines first, run the containment and counting checks, then loop the no-touch eliminations as the grid fills. On Puzzle Lair every Star Battle is guaranteed solvable by logic alone, so if you are stuck there is always a deduction waiting, never a guess. Bigger grids and the two-star puzzles are what make the hard set a genuine workout.

Frequently asked questions

What is Star Battle?: Star Battle, also called Two Not Touch, is a logic puzzle on a grid divided into bold-outlined regions. You place a set number of stars so that every row, every column and every region holds the same count, and no two stars touch, not even diagonally. The number of stars per row, column and region is fixed for each puzzle, either one or two.
What is the no-touch rule in Star Battle?: The no-touch rule says no two stars may sit in cells that touch, including diagonally. Around every star all eight neighbouring cells must stay empty. It is the constraint that makes the puzzle work: each star you place rules its eight neighbours out, which is why marking those cells with excludes is the heart of solving.
How do you start a Star Battle puzzle?: Begin with the tightest region, row or column, the one where the required stars barely fit. Small or thin regions force their stars into a narrow set of cells, letting you exclude that star from the rest of the row or column. Each star you place excludes its eight touching cells, which tightens the neighbouring lines and regions so the grid opens up from its most cramped corner.
What is containment in Star Battle?: Containment is the key counting technique. If every cell a region could use for its star sits within one row or column, that region's star must lie in that line, so you can exclude the star from the rest of the line outside the region. In two-star puzzles you extend it: if two rows can only place their stars in two regions, those regions are full and their other cells are excluded.
Does solving Star Battle ever require guessing?: No. A well-made Star Battle has exactly one solution reachable by pure logic. Every Puzzle Lair Star Battle is generated and verified to be solvable without guessing, so being stuck means there is a deduction you have not spotted yet, often a containment or counting check you have not run. When you think you have placed every star, press Check to test the board. There is no mistake limit.

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