When does the egg-hatching have to begin for the IV reader in Sun/Moon?

Question

In Pokemon S/M, you can have access to an IV reader in the Battle Tree. However, you must hatch 20 eggs to get his attention. When does the hatch-counter start? Does it start after you unlock the Battle Tree or from the beginning of the game?

Comments

Not sure when the counter starts (I'd bet it would be from the beginning) -- but the checker isn't for EVs, it's for IVs. You can see EVs from the start of the game by pressing Y on any Pokemon's summary screen.

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Oops :P
I keep getting those confused. I will edit it. Thank you!

Answer 1

You unlock the Judge function, which allows you to view the IV's of your Pokémon, once you hatch 20 eggs, starting after you beat the Pokémon league and unlock the Battle Tree