0h n0

0h n0 is the companion to 0h h1, made by Martin Kool at the Dutch studio Q42 and released in 2015. Its rules come from the Japanese puzzle Kuromasu, told with dots. 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, every blue dot sees at least one other, and red dots stop the line of sight.

The daily part is the Today's puzzles menu. It names the weekday and offers six grid sizes, from 4x4 to 9x9. Each grid is generated from the day's date and its size, so everyone who opens it on the same date gets the same set, and the menu marks the sizes you have finished. A small grid takes a minute; the 9x9 asks for real care.

The game is built for quick, tidy solving. A tap turns a cell blue, another turns it red, a progress figure counts up under the board, and there is undo, an optional timer and a hint that points at a cell you can fill and explains why. Outside the daily set, free play makes a new random grid each time. The game can be switched between English and Dutch.

There are no ads, no account and no nag screens on the web, and the free apps for iPhone and Android say the same. 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 and no clutter.