What is Swap Breeding?

Question

please explain

Comments

I don't know too much about it myself but from my understanding, you basically use a Pokemon that breeds and hatches fast (like Magikarp) to see how many eggs you get a shiny in, then reset and swap Magikarp for the Pokemon you want shiny, and reject eggs until you get the egg number the shiny Magikarp was in? I think that's the methodology of it, again, I don't know for sure.

I don't know about why that works in the code though.

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Answer 1

Thanks to the fact that SM/USUM think a bit too far ahead, shiny eggs are heavily predetermined, meaning you can pretty much just cheat masuda method breeding.

Lets say you want a shiny Rowlet.

What you need:

• A Pokemon that hatches fast. Like Magikarp. This Pokemons' IVs are irrelevant.
• A Ditto holding the Destiny Knot. This Ditto needs the IVs you want to pass on. Preferably foreign.
• An Everstone, equipped to a Rowlet. This Rowlet needs the IVs and nature you want to pass on.

You breed the Magikarp with the Ditto. Every 30 eggs you get, stop making eggs by emptying the nursery and hatch them. For every 30 eggs you hatch, save.

Keep this up until you get a shiny Magikarp. Lets say you got it on your 13th egg since your last save.

Reset the game without saving.

Swap the Magikarp for your Rowlet. The 13th Rowlet egg is now guaranteed to be shiny.

If you were hatching for a genderless / fixed gender Pokemon, hatch a 14th egg. Genderless and fixed gender Pokemon offset every roll for gender by 1.

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In Summary, since egg shininess is determined so far ahead, you can easily swap the shiny egg for a Pokemon you want to be shiny.

Source