0h h1

0h h1 turns a grid of red and blue tiles into a compact deduction workout. Keep colors balanced, ban three-in-a-row runs, and make every row and column unique. Free play and today's puzzles give the small rule set plenty of repeat business.

What is 0h h1?

Created by Martin Kool at Q42 and launched in 2014, 0h h1 strips the Takuzu idea down to red tiles, blue tiles, and three constraints. Each row and column needs an even color split; triples of one color are forbidden; duplicate rows and columns are out. The home screen offers a how-to, open-ended free play, and a daily-puzzle route, while settings expose hints, a timer toggle, language choices, and several color themes. It is the kind of puzzle where the board looks almost empty until one forced move gives the next few somewhere to stand.

What you can do there

• Fill a red-and-blue grid under three deduction rules
• Choose free play or a daily puzzle
• Use hints when the grid stalls

Why we picked it

The pleasure comes from how much deduction the game squeezes from such a tiny kit. Its two-color board is quick to read, the rules reinforce one another, and a stalled line can suddenly unlock the whole grid without adding lore, currency, or decorative fog.

How to get the most from it

Start with Free play and keep the three checks in rotation: block any possible run of three, balance the two colors in completed lines, then compare nearly finished rows and columns for duplicates. Turn on the hint icon if the board stops yielding forced moves, and use the daily puzzle when you want a defined visit rather than an endless sequence.

Good to know

The browser page presents play as free and also offers a small one-time donation. Google Play sign-in is described as the route to achievements, experience points, and friend leaderboards, while Free play appears separately. Settings list a high-contrast theme, elapsed-time toggle, hints, and language choices; audio behavior and assistive-technology support are not documented.

Who made it, and when?

Martin Kool is the credited creator or organization. The earliest supported launch date we found is 2014.