A brain-training puzzle in which you draw 1 line, that will sharpen your wits.
In this free-to-play puzzle game, you merely have to draw one line. It is deceptively simple, yet profoundly deep.
Play through the extensive stages, sharpening your wits as you have fun.

A brain-training puzzle game that activates your mind as you play.
When you've got a spare moment, on your daily commute, or before going to bed, why not experience what it feels like to activate you mind?

How to play:
There is only one rule:
"Connect all the points with just one line."
It doesn't matter where you start.

There are some fiendishly tricky, complicated puzzles among the large number of stages.
When you get stuck, make use of a hint.

There are 15 levels, and a total of 850 stages.
At first, it starts off with simple shapes, but each time your level increases, the number of lines increases, and it gets more and more complicated.
You might think it's too easy early on.
However, clearing the simple stages is also important.
The hints to clearing the later, more complicated stages can all be found scattered through the simple stages.

Some unique types of line, such as "one way lines" and "overlapping lines", can also be found throughout the stages.
These special lines will encourage your imagination.

Use this chance to activate your mind as you play, by trying to solve this free-to-play brain-training puzzle game.
You're sure to get hooked!!

What’s New

Version 1.9.2

Thank you for always using it.
We have carried out the following update.

* Fixed a bug in which advertisement is displayed to users who have purchased 'Ad delete'
* Improve performance

Please continue your favors toward "1LINE - one-stroke puzzle game" in the future.

Ratings and Reviews

4.7 out of 5
31.9K Ratings
31.9K Ratings
Wolfbane howlin ,

A like minded thinker... Finally!

Who ever created this game is my brother from another mother. It sounds crazy but for the first time in my life I know that at least one other person out there has a similar thought process to me and I don’t feel as alone anymore. This is a game that supposedly measures IQ, but I believe it also shows spiritual intellect by measuring EQ or common sense problem solving skills aka animal instincts. I was diagnosed ADD when it was first coming onto the scene and little was known about it. Basically I am a conceptual thinker not liner... which means my mind bounces around like a ping pong ball. What makes me unique I believe is that I can go off on multiple tangents but still go back and show you how every tangent is connected by the same common thread by slowly going from point to point and metaphorically drawing one line from point to point in many different directions and ways without ever having to retrace or pick up the metaphorical pen and start another line that doesn’t connect to the first line. This game is the literal and physical version of how my subconscious and conscious minds operate as one via the third eye or pineal gland. This is an incredible game and a true gift for me and I just want to say thank you to whomever created it from the bottom of my heart.

Abear & Bee ,

Don’t waste your money buying “ad free” - there’s still ads...

Really fun addicting game. I was enjoying it so much that I decided to go ahead and buy the paid version of the game to remove the ads. I was really enjoying the game without the little pop ups on the bottom or between levels, but found that once I finished about five levels, an ad would pop up right over the “continue” button to watch a video and get a free hint. I have hit that pop up on accident so many times because of its short delay and being right over the button I’m trying to press that I have gotten very frustrated. When I paid to remove the ads, I wanted them ALL gone. A pop up to view an ad is just as bad as an ad itself, especially when it tricks you into clicking on it. Then you have to navigate back to your level and the meditative state from focusing on the game gets totally ruined. The game is good if you don’t mind ads, but DONT WASTE YOUR MONEY trying to get rid of them. That pop up to watch a video after every few levels will alway still be there. Very disappointing. WOULD NOT PURCHASE AGAIN

lifeandall ,

Where to start and finish, and bridges

Kudos to authors for monetizing some very basic graph theory (the topic here is Eulerian circuits and Eulerian trails). Check how many edges sticks out of each vertex. That’s called the “degree” of a vertex. If all vertices have even degrees, then choose any vertex as both your start and finish. If exactly 2 vertices have odd degrees, then those 2 vertices are your start and finish. In that second case (different start and finish), pay attention to vertices and edges called “bridges”. Those are vertices and edges which *must* be on *any* path from the start to the finish, whether it contains all edges or not, they’re *unavoidable* in getting from here to there. Mentally take away those edges and cut these vertices in half, and you’ll have some “islands” (those are called “blocks”). Make sure you use up every edge of each island before you cross the bridge to the next island. Oh, and double edges (they’re dotted) count twice, etc.


120.1 MB
Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, Japanese
Age Rating
Rated 4+
© GameStart
In-App Purchases
  1. Remove ADs $1.99
  2. 5 Hints $0.99
  3. 30 Hints $2.99


  • Game Center

    Challenge friends and check leaderboards and achievements.

  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like