An electronic piano is a keyboard instrument designed to simulate the timbre of a piano (and sometimes a harpsichord or an organ) using analog circuitry.
Electronic Piano was also the trade name used for Wurlitzer's popular line of electric pianos, which were produced from the 1950s to the 1980s, although this was not actually what is now commonly known as an electronic piano. Electronic pianos work similarly to analog synthesizers in that they generate their tones through oscillators, whereas electric pianos are mechanical, their sound being electrified by a pickup.
The first electronic pianos date from the 1970s and were mostly made in Italy (Davies 2001), although similar models were made concurrently in Japan. An exception is the range of instruments made by RMI in the USA from 1967 to approximately 1980, which was used by Genesis, Yes, Deep Purple, Elton John and Rick Wakeman (Reid, 2001). These early electronic pianos (including the RMI) are not velocity sensitive, in that they do not vary their volume based on how hard or soft the keys are played, like an organ. "The major drawback of the RMI was its total lack of touch sensitivity. I found this very restricting, especially since any bum-notes are played at full volume, no matter how lightly you brush against them" (Tony Banks, quoted in Reid 2001).
Electronic pianos became less popular in the 1980s when the digital piano and polyphonic synthesizer became available and affordable enough for both professional and home use as an inexpensive, smaller and lighter alternative to an acoustic piano. The triumph of the synthesized piano first came in 1982, with the development of the Kurzweil K250.
As of 2009, synthesized pianos have attained a remarkable level of realism, with the Yamaha AvantGrand reportedly indistinguishable from a real piano by 95% of pianists (Wilson 2009).