Original: In 1993, Tsuburaya Productions and Toei Company co-produced Ultraman vs. Kamen Rider, a crossover with the original Ultraman and Toei's Kamen Rider 1.
Simplified: In 1993, Tsuburaya Productions and Toei Company co-produced Ultraman vs. Kamen Rider, a connection with the original Ultraman and Toei's Kamen Rider Ichigo.