How to play Eclipse
Suns and moons in balance. Never three in a row.
Play today’s Eclipse →The rules
Fill the grid with suns and moons. Each row and each column ends up with equal numbers of both, and you can never put three of the same symbol in a line. The small "=" and "×" markers between cells tell you where two cells must match, and where they must differ.
- Every cell holds a sun or a moon.
- Each row and each column holds equally many suns and moons.
- Never three identical symbols in a row or column.
- "=" joins two cells that match; "×" joins two that differ.
The techniques, in the order you will need them
This list is doing double duty. Every entry is a deduction the grading solver actually performs, and the difficulty on a board is decided by how far down the list the solver had to go. A puzzle is only labelled beginner if the first rank was enough, and only expert if the last one was genuinely needed. Learn them in order and you are learning the ladder.
Break up a pairBeginner
Two identical symbols side by side cannot become three. Both cells flanking the pair take the other symbol.
Fill a gapBeginner
A gap between two identical symbols must hold the other symbol - otherwise you would have three in a row.
Follow a markerBeginner
An “=” marker copies its neighbour’s symbol; a “×” marker takes the opposite. One known side settles the other.
Line is fullIntermediate
Each row and column holds exactly half suns and half moons. Once one symbol has filled its half, every remaining cell in that line is the other symbol.
Only one way to finish the lineAdvanced
Work out every legal way the line could be completed. Any cell that reads the same in all of them is settled, even if no single simple rule proves it.
Assume and refuteExpert
Suppose a cell is a sun and follow the simple rules. If that leads to an impossible board, the cell must be a moon. You never keep the guess - you only ever rule one out.
Why you will never need to guess
Every Eclipse board we publish has been through an exhaustive search proving it has one answer, then handed to the technique solver above to be solved a second time. Boards that second solver cannot finish are thrown away before they ever reach the calendar. So the difficulty label is not somebody’s impression of how the puzzle feels. It is a statement about which of these techniques you will have to use.
Where to play
- Today’s Daily. One board a day, the same one for everybody, replaced at your local midnight.
- Unlimited. Four difficulties, and it does not run out.
- Archive. Every Daily we have published. Playing an old one cannot break your streak.