"Osu!"

"Osu!" is a free music game that lets you use a mouse, tablet or touch screen to follow along with different songs.

Professional gamers use "Osu!" to practice aiming and improve their mouse skills.

"Osu!" has tons of customization options- you can design your own tracks to play, or download hundreds made by other people online.

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If you've ever wondered how professional gamers keep their mouse skills so sharp, I've found the game for you. "Osu!" is a free music game for computers, inspired by classic Nintendo DS series of rhythm games "Osu! Tatake! Ouedan!"

The gameplay of "Osu!" is simple - you tap a series of circles to the beat of the music, occasionally dragging a ball or rotating a spinner on the screen as well. The game has a ton of customization options and players can make "beat maps" to match their favorite songs and share them with each other online.

Professional gamers frequently use "Osu!" as a warm-up or practice before gaming, especially players who play shooting games like "Fortnite" or "Counter-Strike." For example, Tyler "Ninja" Blevins, the most well-known professional gamer in the world, recommends using "Osu!" in his new book "Get Good."

Read more: I read Ninja's new book on professional gaming - these are the 6 most important things I learned

Even if you're not looking to push your mouse skills to the limit, "Osu!" can still be an addictive pasttime thanks to a limitless library of songs online. To get started with "Osu!," you'll need to download the game first. You'll start with about 40 tracks with a range of difficulties, and can use the same site to search for more.

Here's how to get started with "Osu!"