How to Solve Magnets: Counting and Repulsion Techniques

Updated October 2026

Magnets is a pure deduction puzzle on a 6-by-6 grid that is already cut into 18 domino slots. Your job is to decide, for every slot, whether it holds a magnet and which way round it points, using only the counts printed around the edge and the rule that like poles may not touch. Each board is generated so that exactly one answer fits, and every board is checked to come out from the counting and repulsion rules alone, without guessing. This guide explains how to read the clues, a handful of counting tricks that open almost every board, and a routine that keeps your time down.

Reading the board

The thick white lines mark the slots; each slot covers two neighbouring cells. A slot is either blank, with both cells empty, or a magnet, with one plus cell and one minus cell. The clues sit on all four sides:

• Top (red): how many plus cells each column contains.
• Bottom (blue): how many minus cells each column contains.
• Left (red): how many plus cells each row contains.
• Right (blue): how many minus cells each row contains.

The one placement rule is repulsion: two plus cells may not be side by side or one above the other, and neither may two minus cells. This applies across slot borders. Diagonal contact is fine, and a plus next to a minus is always fine.

Tapping a cell cycles it through plus, minus and blank, and its partner in the slot automatically takes the opposite pole, so one tap sets a whole magnet. Any two equal poles that touch are flagged at once: both squares turn dark red and the two discs get a yellow ring. The puzzle is solved the moment every clue matches and no poles clash.

First, count the magnets

Every magnet contributes exactly one plus cell. That means the six red numbers on the left add up to the total number of magnets on the board, and so do the six blue numbers on the right; the column clues give the same totals. Subtract that total from 18 and you know how many slots are blank.

This sounds minor but it frames the whole solve. In the boards we generated for testing, the median was 9 blank slots out of 18, ranging from 4 to 13, so roughly half the slots are usually empty. Knowing the exact figure tells you when to stop placing magnets in a crowded area and when a sparse area must still hide several.

Zero lines and full lines

Look for zeros first. A row whose red clue is 0 contains no plus cell at all. Any slot that crosses that row vertically is then either blank or has its minus end in that row. Any slot lying flat along the row must be blank, because a flat magnet would put a plus in the row. In our sample, about 89 percent of boards had at least one zero clue, so this is nearly always your opening move.

The opposite case is a line whose red and blue clues add up to 6. Then all six cells in the line are filled and no slot touching that line can be blank there. Now you only need to work out the orientation, and repulsion usually decides it: inside a full line, the poles must alternate plus, minus, plus, minus. About a third of the boards in our sample had such a line.

When a line already has all the plus and minus cells it needs, every remaining cell in it must be blank. Mark that mentally, and the slots crossing into it become decided too.

The balance trick

Here is a deduction that is easy to miss. A slot lying flat inside a row always adds one plus and one minus to that row, so flat slots never change the difference between the row's red and blue clues. Only the slots standing upright, which put just one cell into the row, can make the counts unequal.

So compare the two numbers on each row. If the red clue is 3 and the blue clue is 1, the row has two more plus cells than minus cells, and at least two upright slots must cross it with their plus end there. If exactly two upright slots cross that row, both are magnets and both point plus into it. The same logic works for columns with flat and upright swapped. This check takes seconds and often places the first magnets on an otherwise quiet board.

Repulsion patterns worth knowing

• Stacked pairs flip. If two flat slots sit directly on top of each other and both are magnets, they must point opposite ways: plus over minus and minus over plus. The same holds for two upright slots side by side.
• Neighbours of a plus. Once a cell is plus, every cell touching it across a border cannot be plus. If one of those neighbouring slots must be a magnet, its orientation is now fixed.
• End-to-end chains. Two magnets lying end to end in a row must meet with opposite poles, so a run of them reads plus, minus, plus, minus all the way along.
• Blanks break chains. A blank slot stops repulsion completely. When a long alternating pattern is impossible to fit with the clues, one slot in it is blank.

Solving for time

Your score is the time from pressing Start to the solving tap, rounded to whole seconds, and lower is better. The clock is real time, so it keeps running if you switch apps. The clock starts when you press Start on the Ready card, not when the page loads.

1. Add up the red clues to get the magnet count.
2. Clear the zero lines and fill the full lines.
3. Run the balance check on every row and column.
4. Follow repulsion outward from every pole you have placed.
5. Only then compare the remaining counts line by line.

Because each tap cycles plus, minus, blank, choose which end of a slot to tap so the pole you want appears in one or two taps. From a blank slot, one tap on a cell makes that cell plus, so tap the end you want to be plus rather than cycling the other end twice.

Common mistakes

• Forgetting blanks count. Leaving a slot empty is a decision just like placing a magnet, and the solve is only complete when the empty slots are right too.
• Mixing up the clue sides. Red is always plus and blue always minus. Top and left are plus; bottom and right are minus.
• Leaning on the clash warning. It only appears after two equal poles already touch. Check repulsion before you tap, and you will not have to undo moves.
• Guessing early. Each board has a single solution, and it can always be reached by deduction. If you are stuck, a count or balance check you have not run yet is usually the way forward.

Your best time is saved on your device, and every solve can be sent to the Hall of Fame from the result card.