The electric guitar initially met with skepticism from traditionalists, but country and blues players and jazz instrumentalists soon took to the variety of new tones and sounds that the electric guitar could produce, exploring innovative ways to alter, bend and sustain notes. The instrument's volume and tones proved particularly appealing to the enthusiasts of rock and roll in the 1950s.
"Open" chords get their name from the fact that they generally include strings played open. This means that the strings are played without being pushed down at a fret, which makes chords including them easier to play for beginners. When you start to learn chords, you have to focus on using the right fingers to press down each note and make sure you're pressing the strings down firmly enough.
Guitars have been played since the Renaissance era, after descending from the ancient Greek instrument, the kithara. Or, at least, that's how the theory goes: the only real proof for this is the similarities between the Greek word and the Spanish word, quitarra. Early guitars often had four strings, evolving into the six-string version we know today in the late 1600s. Anton Stradivari, the famous violin-maker, also had a hand in making guitars. There's now only one Stradivarius guitar left in existence.