If I use Greninja's "Water Shuriken" ability first and then evolve to Greninja BREAK on the same turn, would I be able to use its "Water Shuriken" ability again?
No, you cannot. Even though Greninja evolved into Greninja BREAK and retains the Abilities of its previous evolution, it still remembers that it has already used up its once-per-turn Water Shuriken ability for that turn.
Source: TPCi Rules Team (2016-02-11)
If my opponent mulligans several times during setup, may I choose to take 1 card from the top of my deck, look at it, and then decide whether to continue drawing my next mulligan?
When drawing cards for mulligans you must announce how many cards you are going to draw, up to the maximum allowed. If you don't announce a number ahead of time, then you must draw the maximum amount. You don't get to look and decide as each card is drawn.
Source: TPCi Rules Team (2015-11-19)
When constructing a deck, am I limited to 4 total Raichu, including Raichu BREAK?
Actually, BREAK is part of the Pokemon's name. So you can play up to 4 Raichu and up to 4 Raichu BREAK in your deck.
Source: BREAKthrough FAQ (2015-11-19), TPCi Rules Team (2015-11-19)
Can I evolve to a BREAK Pokemon while it is on the bench?
Yes. If follows the normal rules of Evolution.
Source: BREAKthrough FAQ (2015-11-19), TPCi Rules Team (2015-11-19)
Must I have my Deck above my Discard Pile on the field, or can I have it the other way around?
The Deck and Discard Pile must be on the same side of the field (either left or right), arranged one above the other. The standard play layout is to have the Discard Pile below the deck, but having the Deck below the Discard Pile is also permitted.
Source: TPCi Rules Team (2015-09-10)
Must I have my Deck and Discard Pile on the right side of the field, or can I have it on the left side (it's easier for me on the left because I am left-handed)?
The standard play layout is to have the Deck & Discard Pile on the right side and prizes on the left side, but having them the other way around is also permitted.
Source: TPCi Rules Team (2015-09-10)
Checking for Confusion should be the very first thing you deal with after you announce what attack you want to use. Contrary to the "Full Details of Attacking" steps found in some older rulebooks, it must be done prior to making any choices the attack requires (such as choosing an opponent's Pokemon), paying any costs (such as discarding energy), flipping a coin to see if the attack fails, etc. So as soon as you announce which attack you are going to use, you must check for Confusion immediately before proceeding with any requirements of the attack or effects on the attacking Pokemon.
Source: TPCi Rules Team (2014-09-25)
Can you use Devolution Spray or Golurk's "Devolution Punch" attack against a Mega Pokemon, and if so what happens to the Mega Pokemon?
Mega Pokemon are evolved Pokemon, so the Mega Pokemon card is removed, but the underlying Pokemon and all other cards attached stay in play (unless the Pokemon is KO'd, of course).
Source: XY FAQ (2014-02-06), TPCi Rules Team (2014-02-06)
When my opponent fails to draw a Basic Pokemon in their opening hand do I have to draw my card right away, or can I wait to see if there are more Mulligans before drawing my cards?
The Advanced Rules section of the current rulebook indicates the player who did not start over may draw a card for each additional time his or her opponent took a mulligan *after* the player with no Basic Pokemon finally draws a Basic.
Source: TPCi Rules Team (2013-01-03), TPCi Rules Team (2013-11-21)
Can I use Heavy Ball to look for a LEGEND Pokemon half?
No, you cannot. The Retreat Cost is only printed on one half of the LEGEND Pokemon. If it is printed on both cards, then it is a common attribute for both pieces; but since it is printed on only one half it only applies to the LEGEND Pokemon when both pieces are in play.
Source: TPCi Rules Team (2012-04-05)