For a first-time visitor in 2026, 5 days is the "sweet spot" to experience Tokyo’s core neighborhoods without feeling completely overwhelmed. A 3-day itinerary is possible but will feel like a sprint, covering only the "Big Three" (Shibuya/Harajuku, Shinjuku, and Asakusa). With 5 days, you have time for a deep dive into Akihabara (electronics/anime), Ginza (luxury), and a relaxing morning at the Tsukiji Outer Market or the Meiji Shrine. If you have 7 days, you can comfortably add a day trip to Nikko or Kamakura, or spend a full day at Tokyo DisneySea. Tokyo is not a single "city center" but a collection of distinct "cities," each requiring 4-6 hours to explore. Because of the vastness of the transit system and the sheer amount of walking involved (often 20,000+ steps a day), 5 days allows for a sustainable pace that includes time for the city's world-class dining and hidden "izakaya" alleys without burning out early in your Japan trip.