Sideboard(ing) Q.

[bleakill]

Maybe I'm just missing something, but where is it stated that you may not sideboard more cards that you take out? So you will end up with a larger deck, yes, but is it allowed as long as it's still 60+ cards?

[LotusHead]

Maybe I'm just missing something, but where is it stated that you may not sideboard more cards that you take out? So you will end up with a larger deck, yes, but is it allowed as long as it's still 60+ cards?

Without looking up the exact tournie rules, for constructed, your sideboard is always supposed to be 15 or 0 cards. This is true for Vintage, Standard, Extended, Legacy and anything that isn't Limited/Sealed/BoosterDraft  pretty much.

For Limited play, the SB is the cards not maindecked, and in Limited play (Sealed, Draft, etc), you can bring in and take out as many cards as you want, say, IN +3 Lands provided by Store, +2 Bombs, out -1 Sucky Card that I finally Read the Text on (uh, Blue Braids Minion guy/girl).  Total change: +4 maindeck.  In Limited, you just need 40+ cards to start.

Contstructed, SB is always 15 or 0, Maindeck is 60+ (or 60 always if you are ubercore!)

[parallax]

From the Magic: the Gathering Floor Rules:

Constructed tournaments
Before the beginning of the second or subsequent game in a match, players may change the composition of their decks by exchanging cards from their decks for cards in their sideboards. Any card exchange between decks and sideboards must be made on a one-for-one basis to ensure that the sideboards remain at exactly fifteen cards. There are no restrictions on the number of cards a player may exchange this way. Players are not required to reveal how many cards he or she is sideboarding.

The Comprehensive Rules don't cover sideboarding and other tournament procedures. Basically, sideboarding is a rule for Magic Tournaments, not a rule of Magic itself.