Open chords are basic guitar chords that use unfretted strings, allowing them to resonate freely. These chords typically include the notes of the chord played on the lower frets, making them easier for beginners to learn. Common open chords include C major, G major, D major, and E minor. Playing open chords is essential for many popular songs, as they provide a rich, full sound. They are often used in various music genres, including folk, rock, and country. Mastering open chords can help new guitarists build a solid foundation for more advanced techniques and chord progressions.