The highly-anticipated "Pokémon GO" may have suffered through a drought of information in early 2016, but things have since changed after a wave of leaks emerged when the Japanese field testing began last week. Sure, Niantic had requested that no one leak such information, but its 2016 - did it really think that this wouldn't happen?

The leaks in question covered a variety of gameplay aspects ranging from exp gain to even how various Pokémon would be classified. However, the most notable among these, and the focus of this report, is evolution.

Ever since Gen I, various Pokémon needed either a Fire Stone, Water Stone, Thunder Stone, Leaf Stone or Moon Stone to evolve. This has been a recurring feature in the series, with Game Freak even introducing the Sun Stone in Gen II, and the Shiny, Dusk and Dawn Stones in Gen IV. Stone-based evolution is reportedly making its return in Pokemon Go, but it now comes with three new twists:

1. All Pokémon require a stone to evolve.
2. Instead of needing a single stone, Pokemon require multiple stones to evolve and some need more than others.
3. Each stone is unique to a specific species.

It should be noted that stones may not be the official name like before. Other reports refer to these items as crystals, often using them interchangeably.

In any case, as mentioned before, each Pokémon will require a stone to evolve. These stones are made up of individual shards that are obtained through capturing a wild Pokemon, and each shard is unique to that specific species. Each of these shards is collected and catalogued automatically, and a running tally will tell the player how many more they need to collect.

Upon collecting the required number of pieces, the shards form a crystal that players can use on one Pokémon of a given species. Once complete, the crystal dissipates and the player will need to start the process from scratch.

Based on this information, players will need to capture a bunch of the same Pokémon in order to evolve a single one of the same species. Unless there is something missing, this sounds like a hassle, depending on who you're trying to evolve. Maybe there is something you can do with the captured Pokémon beyond merely obtaining the crystal and releasing them that makes the system feel less grindy (maybe feeding them away for experience like in "Puzzles & Dragons").

The other aspect of evolution, i.e. the amount of shards needed, is quite straight forward. Each Pokémon will require a different amount of shards to evolve, and that number is based on their evolutions in the original games. For example, starters like Bulbasaur, Charmander and Squirtle all require 10 shards to evolve to their second stage, then another 10 shards to reach their final one.

For example: Squirtle --> 10 shards --> Wartortle --> 10 shards --> Blastoise.

On the other hand, Pokémon who have only one evolution stage need 20 shards to evolve.

For example: Grimer --> 20 shards --> Muk

Lastly, there is at least one Pokémon who breaks that model entirely: Magikarp, who requires 100 shards before evolving into Gyarados. It's unclear if this is a nod to how long it would take to grind a Magikarp to level 20 before it would evolve if the rest of your team wasn't at a high enough level, or simply due to how strong Gyarados is. If it's the latter, it's possible that other Pokémon who have notably strong final evolutions could receive similar treatment.

With all this talk of stones, its interesting that information about Eevee, the Pokémon most known for stone-based evolution, hasn't turned up yet. With eight evolutions, three of which need a stone, two dependent on the time of day, two based on location and one based on having a move of a specific type, it will be interesting to see what Niantic does.

In the meantime, we'll just have to wait until the field testing comes to the U.S. before we can get a first-hand look.

Check out the definitive guide on Reddit, in a sburedddit titled "The Silph Road," here.