0h n0

About 0h n0

0h n0 is a companion to 0h h1, made by Martin Kool at the Dutch studio Q42. Its rules come from the Japanese puzzle Kuromasu. Every cell becomes a blue or a red dot. Blue dots look along their own row and column, a numbered blue dot must see exactly as many other blue dots as its number, and red dots stop the line of sight.

The game is built for quick, tidy solving. Grids come in several sizes, there is undo, an optional timer, and a hint that points out a cell you can fill and why. Most play is free play, where a new random grid is generated each time.

The daily part is the Today's puzzles menu. There, each grid size is generated from the day's date, so everyone who opens it on the same date gets the same set, and the menu marks which sizes you have done. It turns an endless puzzle into a short daily set you can compare with others.

It suits players who like clean number-logic grids such as the Nikoli-style dailies, and anyone who wants a short puzzle with no words, no account and no clutter.

How to play 0h n0

1. Open 0h n0 and choose Today's puzzles.
2. Pick a grid size.
3. Tap empty cells to make them blue, tap again for red.
4. Make each numbered blue dot see exactly its number of blue dots in its row and column; red dots block the view.
5. Fill every cell to finish, then try the next size.

Tips

• A number equal to all the space it could see means every one of those cells is blue.
• Close off a dot that already sees enough by placing red dots right after its view.
• A blue cell with no number still needs to see at least one other blue dot.
• Use the hint button to learn the standard deductions; it explains the reason.

Questions