A Ton of Helpful rulings

Here is a list of a ton of rulings that will be run into a lot, hopefully it will help some of you out.

Royal Decree:
You can chain royal decree to any trap (That is not a counter trap) and negate it, also you can chain a trap to royal decree and it will not be negated.

Rivalry of warlords/Gozen match:
You can not attempt to normal summon, flip summon, special summon, tribute summon, xyz summon, or syncro summon for other types/attribute of monsters.
You can set cards of different attribute/type face-down but when they are flipped face up after being targeted from an  attack gozen match/rivalry of warlords, will destroy it.

Skill Drain:
The part where it says (But the effect can still be activated) This mean that you can pay cost to the effect.
You can summon malefic monsters without a field spell if Skill drain is on the field, but you still can not control more then one malefic monster since it is a summoning condition.
This card only effects cards that activate and resolve on the field so it can not negate a effect like Stardust Dragon.

Damage step/attack declaration
Attack declaration is one of the first things that occurs when a monster attacks this is the moment to activate cards like mirror force, Dimensional prison and cards of that nature, Stardust Spark Dragon can activate at this point since attack declaration is not considered damage step.
The damage step, is were card that modify attack can be activated card such as forbidden lance, Honest, and Horn of the phantom Beast. At this point you can not activate cards such as mirror force. Counter traps can still be activated at this point.


I am to lazy to write anymore please put rulings down below and i will add them to this list. (Try not to copy and paste big worded descriptions.)
Here are some helpful links
Yu-gi-oh Rule book: http://www.yugioh-card.com/en/rulebook/YGO_RuleBook_EN-v8.pdf
rulings (Advanced rulings): http://forum.duelingnetwork.com/index.php?/user/54151-skulblaka98/
Yugioh Wiki: http://yugioh.wikia.com/wiki/Main_Page