Nightwatch A calm logic puzzle. A new board every night.

The four rules

1. Every courtyard gets exactly one lantern.
2. A lantern lights its own square and shines along its row and column until a wall stops it. A courtyard edge does not stop light, and a lantern set on a lit square is dazzled, which is never allowed.
3. No lantern may shine on another lantern.
4. Every open square must end up lit.

That is the whole game. Every board has one right answer, and you can reach it from what is on the screen, step by step, without a guess. How the deductions work.

What the app adds

Tonight's board is the same here and in the app. The app keeps going after it:

• Seventy campaign rounds in five districts, from five-by-five yards to nine-by-nine streets, each named for the corner of the town it lights.
• Free play with hundreds more boards at every size: gentle, tricky or deep.
• The archive. Past nights wait there, and every streak starts with two spare nights in hand.
• Hints that teach before they tell. The first two are free whenever you want them: one names the technique the board is asking for, the next shows the squares it acts on. A third can point to one square and prove it.
• Offline play. Tonight's round, your saves and the first two hints never need a network. There is no account and no sign-in.

Nightwatch is free, and ads pay for it. Nightwatch Premium is one payment of $4.99: it turns off the ads between boards for good, and hints are free, every time.

One answer, never a guess

We ran every board in Nightwatch through the game's own solver: 1,651 in all. Each has exactly one solution, and each can be finished with six named deductions, without a guess. How the check works.

Learn the deductions

• Light Up (Akari): the rules, and how to play
• How to solve Light Up: six deductions, step by step
• Regional Akari: Light Up with courtyards
• How to play Sudoku, and the other kinds of logic puzzle