Pokémon Pikachu, also known as in Japan, is a series of portable Pokémon digital pet

Digital pet

A digital pet is a type of artificial human companion. They are usually kept for companionship or enjoyment. People may keep a digital pet in lieu of a real pet....

s featuring the famous yellow electric Pokémon, Pikachu

Pikachu

is one of the species of Pokémon creatures from the Pokémon media franchise—a collection of video games, anime, manga, books, trading cards, and other media created by Satoshi Tajiri. As do all Pokémon, Pikachu fight other Pokémon in battles central to the anime, manga, and games of the series...

. This product was intended as an exercise toy and mentioned by Guinness World Records

Guinness World Records

Guinness World Records, known until 2000 as The Guinness Book of Records , is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world...

 as the most popular exercise toy of its time. The first release of the device was simply called "Pokémon Pikachu." A yellow unit resembling a Game Boy, it features a black and white LCD screen used to display animations of Pikachu's activities. The second release, Pokémon Pikachu 2 GS, was available in clear and silver casing with a color display featuring more animations.
Both of the Pokémon Pikachu incarnations differ slightly from more traditional portable virtual pets in that Pikachu does not need to be fed, watered, or cleaned up after. Instead, the Pokémon Pikachu unit can be strapped to a belt and used as a pedometer

Pedometer

A pedometer is a device, usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of the person's hips...

. With every step it counts, the Pokémon Pikachu credits its user with "watts," which are a sort of currency used to buy Pikachu presents. About twenty steps on the pedometer will reward the player with one watt. As the player grows closer to Pikachu, more activities become available. However, if neglected, Pikachu will become angry and eventually refuse to recognize the player.
Pokémon Pikachu 2 GS features an infrared port for interacting with Pokémon Gold, Silver

Pokémon Gold and Silver

are the second installments of the Pokémon series of role-playing video games developed by Game Freak and published by Nintendo for the Game Boy Color. The games have dual-mode capabilities allowing them to also be played on earlier Game Boy models. They were first released in Japan in 1999 and to...

, and Crystal via the Mystery Gift option, which uses the Game Boy Color

Game Boy Color

The is Nintendo's successor to the 8-bit Game Boy handheld game console, and was released on October 21, 1998 in Japan, November 19, 1998 in North America, November 23, 1998 in Europe and November 27, 1998 in the United Kingdom. It features a color screen and is slightly thicker and taller than...

's built-in infrared communication port. This mode allows players of the Game Boy titles to trade their Pokémon Pikachu's watts for items to use in the Game Boy game. Although there is a limitation on how much the Mystery Gift mode can be used between Game Boy cartridges, Pokémon Pikachu's only limit is that of available watts. Watts can also be sent to other Pokémon Pikachu 2 units.

Other models

Pokémon and its character, Pikachu were not the only media franchises that were used by this Nintendo-made device. Sakura Taisen, a media franchise of SEGA

Sega

, usually styled as SEGA, is a multinational video game software developer and an arcade software and hardware development company headquartered in Ōta, Tokyo, Japan, with various offices around the world...

 and licensed by RED Entertainment

Red Entertainment

is a video game developer based in Japan. Formerly known as since is foundation in 1976 , it was reorganized under its current moniker on December 4, 2000...

 released a virtual-pet with pedometer in the same style as the Pokemon Pikachu 2 called Pocket Sakura (ポケットサクラ). It was released alongside Sakura Taisen GB, they were developed by Jupiter

Jupiter (company)

Jupiter Corporation is a Japanese video game and hardware development studio that focuses on handheld consoles. It is based in Kyoto, though they have a secondary branch in Tokyo...

. Sega could not publish either of them because they were rivals at the time with Nintendo, so publishing was handled by Media Factory

Media Factory

is a Japanese publisher. It was founded on December 1, 1986, and its headquarters are situated in Shibuya, Tokyo. It is a subsidiary of Recruit Co., Ltd...

.

Similarly, Sanrio

Sanrio

is a Japanese company that designs, licenses and produces products focusing on the kawaii segment of Japanese popular culture. Their products include stationery, school supplies, gifts and accessories that are sold worldwide and at specialty brand retail stores in Japan...

, responsible of the Hello Kitty

Hello Kitty

is a fictional character produced by the Japanese company Sanrio, first designed by Yuko Shimizu. She is portrayed as a female white Japanese bobtail cat with a red bow. The character's first appearance on an item, a vinyl coin purse, was introduced in Japan in 1974 and brought to the United States...

 franchise licensed to Nintendo the development of the Pocket Hello Kitty, which was a version of the first Pokemon Pikachu, just with different software/game, this time based in Hello Kitty and her friends and in a pink colored case.

Pokéwalker

A device similar to the Pokémon Pikachu, called the Pokéwalker, comes packaged with Pokémon HeartGold and SoulSilver

Pokémon HeartGold and SoulSilver

are enhanced remakes of the 1999 video games Pokémon Gold and Silver. The games are part of the Pokémon series of role-playing video games, and were developed by Game Freak and published by Nintendo for the Nintendo DS...

and communicates directly with the game cards via infrared. It allows the player to transfer one Pokémon at a time from their HeartGold or SoulSilver. The user is able to catch Pokémon and find items by spending watts.