Backward chaining is a method of reasoning that works backward from a goal to determine if the goal can be proven true based on available information. It assumes a goal and works to find rules and facts that support that goal. For example, if the goal is to determine if a new pet Fritz is green, it can be proven in four steps by applying rules: 1) Fritz croaks and eats flies, so by rule 1 Fritz is a frog, 2) if Fritz is a frog then by rule 3 Fritz is green, thus proving the goal that Fritz is green. Backward chaining is useful for goal-driven and diagnostic applications where the goal is to determine if a hypothesis can be supported through available data.