The "black phone" (kuro-denwa) is the colloquial Japanese name for the black-cased rotary dial landline. Its formal designation is the Type 600 automatic desk telephone, introduced in 1962 by Nippon Telegraph and Telephone Public Corporation, the predecessor of NTT. The earlier Type 4 telephone, in service from 1950, was also black and is called a black phone too, but the Type 600 was by far the most widely distributed, so it is the model people picture.
Black phones spread quickly through Japanese homes during the postwar growth decades. Line construction could not keep up with demand, and for years households that had applied for service were left waiting, a backlog known in Japanese as shakutai. The backlog was cleared, and dialing directly to anywhere in the country became possible, only in the late 1970s. As subscriber lines multiplied in that period, the black phone came to stand for the one-per-household era: a single set on a stand in the hall or entryway, shared by the whole family.
To dial, you placed a finger in the hole for the digit, turned the dial to the stop, and released it, and the dial returned on its own at a fixed mechanical speed. Larger digits therefore took longer, with "0" needing about one second. The emergency numbers 110 and 119, built from digits that require only a short turn, could be dialed quickly under that mechanism. Once push-button phones appeared in 1969, rotary models were gradually replaced.
A black phone runs on current supplied over the telephone line, so it needs no wall outlet and still works in a blackout as long as the subscriber line is alive. Cordless handsets and IP phones on fiber go dead without power, which is why some households keep a black phone as an emergency backup. Note, though, that Japan's fixed-line network began migrating to IP in January 2024 and finished by January 2025. A household still on an analog subscriber line does not need to swap out the telephone, but when connecting to an IP phone service over fiber, some equipment will not accept the pulse signals a rotary dial sends, so compatibility must be confirmed. And wherever a call requires tone key entry, such as an IVR menu, a rotary dial cannot handle it.
Black phones have a durable following as retro decor, with good-condition Type 600 units trading for a few thousand to a few tens of thousands of yen. See the history of telephone hardware and the origin of "moshi-moshi" for more on Showa-era telephone culture.