The Imperial Palace is the Emperor of Japan's primary residence at the heart of Tokyo, built on the former grounds of Edo Castle. Most of it is off-limits — what you actually see is the outer grounds and the free East Gardens.
The Imperial Palace looks iconic on a map and shows up on every Tokyo itinerary, but the honest truth is that most of what's here is inaccessible — the inner palace buildings are strictly private. What you can visit is the East Gardens (free, open to the public) and the surrounding grounds, which include massive stone walls, ruins of the original Edo Castle foundation, a Japanese garden with a tranquil pond, and seasonal flowers. The real decision is whether that's worth your time against everything else Tokyo is throwing at you.
Worth a visit if you go early and set realistic expectations — the inner palace is off-limits, so you're here for the East Gardens, stone walls, and Edo Castle ruins, not a grand palace interior.
The East Gardens and outer grounds are free to enter; no ticket is required for the public areas.
Arrive when the East Gardens open at 09:00, enter via the Ōte-mon Gate, and check ahead since the site is typically closed Mondays and Fridays — if crowds are already heavy, consider the outer moat walk or swap the whole visit for Rikugien.