The "black phone" (kuro-denwa) is the colloquial name for black-cased rotary dial landlines. Officially the "Type 600 Automatic Desk Telephone," it was introduced by NTT's predecessor in 1962. While the earlier "Type 4" (1950s) was also black, "black phone" typically refers to the Type 600.
Black phones spread rapidly during Japan's high-growth era. Demand was so intense that installation backlogs became a social issue by 1965. By 1975, subscriber lines exceeded 30 million. The black phone symbolized the "one per household" era, placed on hallway phone stands and shared by the entire family.
Rotary dialing involved inserting a finger into the numbered hole, rotating to the stop, and releasing for automatic return. Dialing "0" took about 1 second, which is why emergency numbers 110 and 119 use many "1"s for faster dialing. Push-button phones from 1969 gradually replaced rotary models.
Black phones still work today but can't navigate IVR button menus, limiting practicality. They remain popular as retro decor, with good-condition Type 600s trading for thousands to tens of thousands of yen. See telephone evolution and origin of moshi-moshi for Showa telephone culture.