Pokémon Go was one of the first games to use augmented-reality technology when it was introduced in July 2016. Before long, 28.5 million users were roaming the streets at odd hours, eyes glued to their smartphones, even stumbling into unexpected places.

Pokémon Sleep, by contrast, will track sleep patterns and change the game based on how long the user sleeps, and what time he or she wakes up. The game will be developed with Niantic, the maker of Pokémon Go, and the game design firm Select Button.

Part of the motivation behind the new game is the need for a good night's sleep.
The companies involved in making the game released few details of how exactly sleep would be rewarded. Nintendo America, which owns part of the Pokémon franchise, will produce a separate sleep-tracking device called the Pokémon Go Plus+. When tucked beneath the user's pillow, it would send sleep data to a smartphone via Bluetooth.
Pokémon Go created a worldwide obsession when it was introduced three years ago, but within five months the app had lost more than 80 percent of its active users, according to comScore, an American company that tracks media analytics.

Pokémon wants to captivate users again, awake or otherwise.

"Everyone spends a large part of their lives sleeping, and turning that into entertainment is our next challenge," Tsunekazu Ishihara, Pokémon's chief executive.
But while Pokémon Sleep may become a hit, won't most users would probably lose interest eventually, as they did with Pokémon Go?.

Many fitness trackers, smartwatches and even smartphones already track sleep patterns, and most at an even more sophisticated level than what Pokémon Sleep seems to be doing. Users might be turned off by having to buy the external sleep-tracking device for additional features.