A vanity number is a phone number made easy to remember by reading its digits as words in Japanese. In English they are called Vanity Numbers, and in corporate advertising and branding strategies, they achieve high memorability by being repeated in TV and radio commercials.
Japanese number wordplay leverages the rich variety of on'yomi and kun'yomi readings. For example, "4" can be read as "yo" or "shi," and "9" as "ku" or "kyu," giving great flexibility in combinations. Famous examples include "0123" for moving services (Nippon Express) and "0120-444-444" (Duskin). Combining wordplay with toll-free numbers (0120) or freephone numbers (0800) creates a synergy of free-call reassurance and memorability, reportedly doubling or tripling phone response rates from advertising compared to regular numbers.
How to obtain a vanity number depends on the number type. For toll-free numbers, you apply to NTT Communications with your preferred number, but popular numbers are often already taken, and some are purchased from number brokers. For landline numbers, the number allocation system generally does not allow specifying a particular number. However, virtual phone number services may let you choose from several candidates with good wordplay.
Note that Japanese number wordplay only works for Japanese speakers, so its effectiveness diminishes for businesses with many foreign customers. Also, overly elaborate wordplay can actually be harder to remember, so simple, intuitive readings should be prioritized. See Business Phone Number Guide for number selection strategies and Free Dial Business Benefits for cost-effectiveness analysis.