0h n0 4+

Q42 B.V.

Designed for iPad

    • 4.9 • 117 Ratings
    • Free
    • Offers In-App Purchases



It's 0h h1's companion game!

Remember that little logic game called 0h h1? Well, we've made a challenging new puzzle game to go along with it! Meet its companion... 0h n0.

0h n0 is a lovely little logic game that follows its own three rules:

- Blue dots can see others in their own row and column.
- Their numbers tell how many.
- Red dots block their view.

It's up to you to complete the grid without ever having to guess. Simply tap a tile to make it blue or red and complete the grid. 0h n0 gives you unlimited puzzles for all four grid sizes:

5 x 5
6 x 6
7 x 7
8 x 8

And now included: 4 x 4 and 9 x 9 boards!

Each puzzle can be played in perfect Zen mode without any pressure. But you can attempt to beat your personal best time in the game's time trials, unlock fun achievements and compete with friends in leaderboards.

0h n0 is free, without ads, without social network requirements, without locked features and without nag screens. 0h n0 is a little gift to you. We hope you enjoy it.

0h n0 can also be played on 0hn0.com.
And if you haven't played its sibling yet, go visit 0hh1.com.

What’s New

Version 1.0.6

This app has been updated by Apple to display the Apple Watch app icon.

Updated for iOS 11.

Ratings and Reviews

4.9 out of 5
117 Ratings

117 Ratings

Anon Ymos ,

ADHD Focus aid

This game has served as an ideal aid for me to pay better attention to college lectures. It has no required auditory components and requires no reading, while providing a sufficiently challenging puzzle ti prevent my mind from wandering while not being so complicated I ignore the lecture I am listening to.
It has no necessary time component, so the game can be paused and resumed at any time, allowing me to take notes as necessary or otherwise engage in class as needed.

Both games in the series have been incredibly helpful, and are fun in their own right. I'm thankful to the devs for creating and maintaining these titles.
Now working as a professional counselor, I recommend these games to my ADHD clients who are under-stimulated in lecture settings

kuma_no_pooh ,

I love this game

This is still, after quite a few years, one of my favorite “go to” (uh, “g0 t0”?) games on the iPad. I know it hasn’t been updated in ages, and I’m fine with that, but one day I hope the developer can treat us to a new version with larger puzzles. 9x9s are too easy after a few thousand of them. :)

Papa mison ,

Great game

Similar to “oh hi” in that it requires some basic pattern recognition, and quick thinking. Better than “oh hi” because it’s a bit more complex and requires some math skills. Great way to wake up your brain when competing against the clock.

App Privacy

The developer, Q42 B.V., has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Game Center

    Challenge friends and check leaderboards and achievements.

More By This Developer

0h h1
Flippy Bit & the Hexadecimals
Hue Clips
Social Networking

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