Takuzu 14×14
A full-size board: 196 cells, seven suns and seven moons in every row and every column. Same three rules as a small takuzu, and still exactly one solution reachable by pure deduction — but at this width the deductions arrive in a different order.
14×14 · 49 cells given (25%) · one guaranteed solution
How today’s board is solved
Step by step, with no guessing. Every move below follows from the ones above it.
This board needs 147 deduced moves: 101 × no-three-in-a-row, 27 × line balance and 19 × contradiction.
Careful: this is the full reasoning. Play first if you would rather work it out yourself.
- K1 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- N1 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- B2 — the two cells before it are moons, and three in a row is not allowed, so it has to be a sun
- L2 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- A3 — the two cells before it are moons, and three in a row is not allowed, so it has to be a sun
- E3 — the two cells before it are moons, and three in a row is not allowed, so it has to be a sun
- I3 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- M3 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- B4 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- A5 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
- M5 — the two cells before it are moons, and three in a row is not allowed, so it has to be a sun
- M4 — the two cells before it are suns, and three in a row is not allowed, so it has to be a moon
The remaining 135 moves follow the same way.
What changes on a 14×14
On a 6×6 board the balance rule bites almost immediately: three suns in a row and the rest of that line is forced. On a 14×14 you need seven of each symbol per line, so a row with four suns already placed still says very little on its own. The board rewards a different habit — instead of finishing one line, you collect small certainties across many lines and let them meet.
The other change is arithmetic. A 6×6 grid has 12 lines to satisfy; a 14×14 has 28, and every cell you fill belongs to one row and one column that both have to stay legal. That is why a big board can feel stuck and then open all at once: a single deduction often completes a line, which completes a count, which forces a run somewhere else entirely.
The rules, at this size
- Never three in a row No three suns or three moons touching, across or down. With 14 cells per line this is the rule that fires most often — it is what the deduction list above is mostly made of.
- Seven and seven Every row and every column holds exactly seven suns and seven moons. Once a line has seven of one symbol, every remaining cell in it is decided.
- One solution, no guessing The board is generated so that a chain of deductions reaches the answer. If you are stuck, there is a cell somewhere that is already forced — the information is on the grid.
Three techniques that pay off on a big grid
Scan for pairs, not for singles. Two identical symbols side by side force the cells at both ends to be the opposite. On a wide row that one pattern resolves two cells at once and often creates the next pair two columns over.
Read the gaps. A gap of one cell between two identical symbols has to hold the opposite: sun, empty, sun means the middle is a moon. This is the deduction that keeps a 14×14 moving when no line is anywhere near full.
Count late, not early. The balance rule is powerful but slow to apply here. Use it when a line already has five or six of a symbol; before that, the no-three rule will almost always give you more for less effort.
Where the 14×14 fits in Solsticio
Solsticio's daily puzzle is a 6×6 — small enough to finish with a coffee, and the same board for everyone that day. The free Android app opens 8×8 boards from the fourth world on. This page is where the full-size version lives: one fixed 14×14, the same for every visitor, playable as often as you like.
If the deductions above are new to you, how to solve walks through each technique on a smaller grid, and what is Takuzu covers where the puzzle comes from and the other names it goes by — Binairo, Binary Puzzle, Sun & Moon.