 Nonaka encountered discrimination in his youth as a member of the "burakumin" group; he later said this discrimination was a factor in his decision to leave JNR and enter politics.He entered local politics in Sonobe, where he served as a member of the local assembly from 1951 to 1958, and as mayor from 1958 to 1966.He then won a seat in the Kyoto prefectural assembly and served from 1967 to 1978.