Pure rock n' roll.
There were many pioneers of rock n' roll debuting at this time, and many were guitar-based: Chuck Berry, Elvis, Buddy Holly, etc.
But this era also saw Little Richard, Jerry Lee Lewis, and others make the piano just as synonymous with the sound.
But a great piano part only goes so far, no matter how insanely hard and well you play it. It's not too hard to figure this one out. Little Richard can siiiiiiiiiing!