In yugioh what's a side deck?

Question

i have been away for a long time wats a side deck

Answer 1

A side deck is 15 cards set aside to be switch with the main deck in between a MATCH to adapt to a certain situation...

When switching, you can only switch the an amount of cards from your main deck for a same amount of card from the side deck..(3-3,2-2,4-4...)

Answer 2

A side deck is basically 15 cards that you can use to switch out between your deck and side deck.

Answer 3

A "Side Deck" is a small pile of cards (15 to be exact). This pile of cards is used to switched cards in and out of your deck between duels.

The purpose of the Side Deck is to adapt to different opponents.

The Side Deck cannot drop below or go above 15 cards.

You cannot have monsters with the same name more than three times between the Main Deck, Side Deck and Fusion Deck. Example: I have 3 Harpie Lady 1s in my Main Deck, thus I cannot place 3 Harpie Lady 2 in my Side Deck because it counts as "Harpie Lady." Also if a card is Limited or Semi-Limited, you cannot have additional copies of it in your Side Deck. So basically the Forbidden List applies to all three posible decks.