Shizuoka is easy to underrate from the Tokaido Shinkansen, where it can look like another large city between Tokyo and Nagoya. Step off the train and the place becomes much more specific: Suruga Bay seafood, green tea hills, Tokugawa history, and some of Japan's cleanest views of Mount Fuji when the weather cooperates.
The best day links Nihondaira, Kunozan Toshogu Shrine, and Miho no Matsubara. That gives you tea fields and Fuji views, a national-treasure shrine tied to Tokugawa Ieyasu, and the pine-fringed coast that became part of the Mount Fuji World Heritage listing. In the centre, Sunpu Castle Park and Shizuoka Sengen Shrine bring Ieyasu's story back into the city.
Shizuoka is not as polished as Kyoto or as immediate as Tokyo, and that is partly why it works. It is a practical, lived-in city with excellent food, good rail access, and enough first-rate anchors to reward a spare day rather than merely filling one.