Ruling

From Yu-Gi-Oh!

A Ruling is when either a Judge, Upper Deck or Konami itself issues a statement clarifying a card's specific relationship with another card.

Unofficial Rulings are not issued from Konami or Upper Deck but are based on official rulings and applicable in most scenarios.

OCG Rulings (often refered to as Japanese Rulings) are rulings issued by Konami. They apply to the OCG and sometimes differ from their TCG counterparts.