Anticipated free-to-play mobile game Pokémon Go is currently being beta tested by lucky fans in Japan, which has resulted in a slew of new details leaking after some web-sleuths managed to delve into the game's files and unearth some of Go's secrets.

Most notable among those secrets is the discovering that Go will start with just the original 151 Pokémon on its roster, presumably so that developers Niantic and The Pokémon Company can bolster and re-energise the game with future updates that introduce the remaining 570 Pokémon.

The discoveries (gathered in this Reddit thread) also include that Go will include all Pokémon types (including Fairy, the most recently-introduced) and seven "natures" - Stoic, Guardian, Assassin, Raider, Protector, Sentry, and Champion. There's nothing indicating how these will impact gameplay however.

Players will need to collect "evolution shards" for wild Pokémon to form "evolution stones" that prompt Pokémon to evolve. It's not clear if this will be required of all Pokémon or a selection that need stones to evolve, as in the main series.

Players will be able to customise their trainer with a total of 52 items resulting in over 23,000 possible combinations. There is also an apparent level cap of 50. Items that can be found or bought include Pokéballs, Potions, Revives and types of berry that only work outside of battle.

The three teams players side with in the game are Red, Blue and Yellow – these teams will fight for control of gyms, as explained in the new details Niantic revealed in late March.

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