The Yo-kai Watch is a wristwatch device enabling communication with and summoning of Yo-kai entities. Its origins trace back to the ancient Genyou tribe's creation, the Elder Magic Mirror, later modified into the Yo-kai Watch Arcane. This artifact was protected in the human world before select individuals became its operators. Centuries ago, Yopple Inc., a Yo-kai World technology company, initiated mass production of early watch models. Whisper, a Yo-kai butler, distributed these devices after being freed from confinement. The first human-made version, the Yo-kai Watch Model Zero, was engineered 60 years prior to the main events by Nathaniel Adams using an old wristwatch and a mysterious marble component; Yopple Inc. later adopted and produced this model. Functionally, the watch detects nearby Yo-kai through a searchlight mechanism and summons them via inserted Yo-kai Medals. Each of the eight primary Yo-kai tribes corresponds to a unique summoning song and colored light matching their tribe symbol. Incorrect medal insertion prevents summoning. Summoned Yo-kai arrive through a circular portal, though long-distance summoning is ineffective. The device occasionally disables summoning during specific holidays. Physical variations exist across models, typically worn on the left wrist with a buckled strap. The watch face displays abstract wisps in pink, light-blue, purple, and green against a black background. Compatibility is restricted to chosen users; unauthorized handling renders it nonfunctional. The searchlight mechanism differs by model—emerging as a separate beam in the original version, but emitting from the clock face in the Yo-kai Watch Dream. Multiple models have been developed. The standard Yo-kai Watch summons Yo-kai using silver-framed or gold Legendary medals, playing tribe-specific songs. Katie Forester’s variant resembles a heart-adorned pocket watch. The Model Zero, created by Nathaniel Adams, features a distinct red body with dial-based activation; it accepts Z-Medals (green-framed) and Classic Medals (dull red-framed), featuring instrumental summoning tunes. The Yo-kai Watch U, a light-blue prototype by Mark Orckerberg, supports all prior medal types plus exclusive U-Medals and 'Merican Medals; its summoning includes a Yo-kai announcer and stage-like visuals. The Yo-kai Watch Dream incorporates win-or-lose roulette mechanics. Post-Yo-kai Watch Shadowside, most models were destroyed except the near-complete Yo-kai Watch Arcane. In spin-offs like *Yo-kai Watch Jam: Yo-kai Academy Y*, specialized models such as the DX A Watch appear. This variant uses Yokai Y Medals to transform users into Yokai HEROes like Mist Shadow; activating special moves requires Command Medals, expanding the device’s utility beyond traditional summoning.