HOW do you get Pikachu on to a bus? You Pokémon! OK, it’s an old joke; but the good news is that the children of today who might be amused by it were not around when Pokémon first hit the streets 20 years ago.

Pokémon is back. And, in its new form, Pokémon Go, it is taking the gaming world by storm, attracting many players who would not describe themselves as gamers. Some churches are even using it as a form of soft evangelism by providing a welcome to Pokémon Go players (News, 22 July; Diary, 12 August). In the first 20 days since its release, on 6 July, it had generated revenues in excess of $75 million. One week later, that figure had risen to $160 million. And it continues to rise.

So, what is it? Pokémon are Pocket Monsters — 722 individual species. Many of these evolved from the list of 151 original species. The aim of Pokémon Go is for the user to capture as many of those original Pokémon as he or she can by throwing the weapon, the Pokéball, in their direction. If it lands on them, you have captured them.

The game uses what is known as augmented reality. The reality is the images picked up by your phone’s camera, and maps based on your device’s GPS location; this is augmented by the computer-generated images of the Pokémon and the Pokéball.

This means that the “playing board”, for want of a better phrase, is the world around you. And it is this that has resulted in criticism about the game. In a typical app, the playing board — or in-app world — is a fictional scene created and controlled by the game’s makers. In augmented reality, the playing surface is the real world.

If an augmented reality game is based around a relatively small area — London, say, or Disneyland — the creators could programme the playing areas to be in deliberately specified places. But when the playing surface is the entire world, it becomes more difficult: there is not enough time to programme in sufficient places; so the creators of Pokémon Go have used algorithms to programme public locations as the hiding places for the Pokémon — known as Pokéstops; or battle grounds, known as Pokégyms.

Although not everybody appreciates the computer-selected locations, others welcome the designation of their public building as a Pokéstop or Pokégym, including churches, who recognise the opportunities provided by the new type of visitor. The C of E’s digital media officer, Tallie Proud, encouraged churches to follow the example of Christ Church, Stone, in Staffordshire, which hosted a Poképarty for people to play the game together.

There are other concerns, too, not least about safeguarding. Concerns have been expressed that people who seek to harm children could hang around Pokéstops and Pokégyms waiting for unaccompanied children to arrive. The NSPCC has published guidance on its website for keeping children safe while playing Pokémon Go.

Pokémon Go is free to download for iOS and Android, with optional in-game purchases. Two additional games, Pokémon Sun and Pokémon Moon, are scheduled for release in November.

bit.ly/pokenspcc