It was the ϕ meson's unexpected propensity to decay into K0 and K0 that led to the discovery of the OZI rule.

[2] The existence of the ϕ meson was first proposed by the Japanese American particle physicist, J. J. Sakurai, in 1962 as a resonance state between the K0 and the K0.

[3] It was discovered later by Connolly et al. (1963) in a 20 inch hydrogen bubble chamber at the Alternating Gradient Synchrotron (AGS) in Brookhaven National Laboratory in Uptown, NY while they were studying K−p+ collisions at approximately 2.23 GeV/c.

[4][5] In essence, the reaction involved a beam of K−s being accelerated to high energies to collide with protons.

The most energetically favored mode involves the ϕ meson decaying into three pions, which is what would naïvely be expected.

[6] Between 1963 and 1966, three people, Susumu Okubo, George Zweig, and Jugoro Iizuka, each independently proposed a rule to account for the observed suppression of the three pion decay.