Dowsing Device

An object, such as a forked branch or wooden stick, used to locate hidden objects by consulting supernatural or magical forces. The Dowsing Device itself is not necessarily magical, but it functions as a focus at least.

Another variation is to use a pendulum, either by carrying it and following the direction of its movement or by holding it over a map.

This is a very old "folk magic" idea in the real world. In fiction, it tends to be used either as Functional Magic or as something for the skeptic to snark at - or sometimes, both at the same time.

Anime and Manga

 * James uses one in an episode of Pokémon.
 * Numata of Kurosagi Corpse Delivery Service normally uses a pendulum to dowse for corpses. In one story, however, he uses the more traditional bent sticks.
 * JK's Iconic Item in Seikimatsu Occult Gakuin. He can also use them as weapons, lockpicks and pretty much anything else.
 * Eila uses one in Strike Witches 2, episode seven, to track down the Neuroi that's been invading the girls' pants.
 * Kurapika in Hunter X Hunter uses one of his nen chains to locate people among others.

Comic Books

 * In Tintin, Professor Calculus occasionally attempts dowsing with a pendulum. Its success varies, but it generally finds something he's looking for but doesn't know he's looking for.

Film

 * In The Princess Bride, Inigo prays to his late father to guide his sword -- then successfully divines the entrance to the Pit Of Despair.
 * Coraline (at least in the movie version) uses one that turns out to be made of poison oak.
 * The Thing That Couldn't Die (a horror film which would have languished in well-deserved obscurity had Mike and the Bots not discovered it) centers around a young girl who can 'water-witch' and consequently discovers the body of a man (justly) condemned to a Fate Worse Than Death.

Live Action TV
"Grandpa: Ah! Here it is! cackles with glee My radio direction finder. Herman: Direction finder? Grandpa, that's just an old-fashioned divining rod! Grandpa: True, true, heh, but I had it transistorized last month! Dials show that the direction finder can be set to find Water, Girls, Metal and Flying Objects."
 * The Munsters: Grandpa Munster had a transistorized one with multiple settings.


 * Gilligan used a divining rod in an episode of Gilligan's Island.

Newspaper Comics

 * Modesty Blaise recurring character Dinah Collier is an effective pendulum dowser (and blind).

Video Games

 * Pokémon has the Itemfinder, also called the Dowsing Machine in Japan and, internationally, from Generation IV onwards. The Pokétch, introduced in Pokémon Diamond Pearl and Platinum, features a Dowsing Machine application which essentially performs the same function.
 * In the first Broken Sword game, George briefly uses a divining rod to find an ancient well (he finds nothing but an extremely old tin can, but when he tosses it aside...).
 * Persona 4: Ms Sofue has one. One sidequest requires the MC to get special materials for her to build a new one once her old one has "stopped responding to her powers".
 * In Touhou, dowsing is Nazrin's schtick. Her rods appear to be weather vanes. Also uses a crystal pendant.
 * The Legend of Zelda: Skyward Sword has this as a main mechanic, to search for keys, pick-ups and Zelda.

Western Animation

 * The Superhero Squad Show episode "Mysterious Mayhem at Mutant High": The Ringmaster has a divining rod that can find fractals.
 * Used in the first episode of Total Drama World Tour.
 * In one Looney Tunes short, Wile E. Coyote gets his tail on fire, so he uses a divining rod to find for water to douse it.
 * In the Ren and Stimpy episode "Royal Canadian Kilted Yaksmen", one is used to find a vein of Canada's greatest resource: dirt. It consists of a shovel with some fruit placed on top.

Real Life

 * Dowsing is Older Than Steam, as seen here.
 * Still in use, as seen in this ad and this video.
 * There is a theory behind dowsing based on the change in gravity over large underground gaps or caves (like a subterranean water pocket compared to surrounding rock), which could be felt in the pendulum (either fork, rod, or actual pendulum, the important thing is it moves in a pendulum like fashion) by a highly trained and very sensitive operator. However, he or she should be sensitive as hell to feel such an infinitesimal change in oscillation by hands only.