Directory assistance (104) is NTT's service where operators look up phone numbers when given a name and address. Continuing from the telephone operator era, it costs 66 yen per inquiry with a 550 yen/month flat-rate option.
Only numbers registered for directory listing (Town Page/Hello Page) are provided. After Hello Page's 2023 discontinuation, NTT database-registered numbers remain available. Unlisted numbers and mobile numbers are not provided.
Usage has declined dramatically as internet search engines and phone number lookup sites offer free alternatives. Annual 104 inquiries dropped from about 1 billion at peak to tens of millions in the 2020s.
Other 3-digit services include 117 (time), 177 (weather), and 113 (fault reporting). While long-standing telephone network services, smartphone apps now substitute most, and usage continues declining. See extinct phone numbers for discontinued service numbers.