A3-2 The main difference is whether the invention undergoes substantive examination or not. Though substantive examination is necessary to determine the existence of novelty, inventive step, etc. when it comes to obtaining a patent right, a utility model is registered without undergoing any substantive examination, as long as it meets the formal and basic requirements that are stipulated under Article 6-2 of the Utility Model Act.
As a result, the validity of a utility model right is actually uncertain since it does not undergo substantive examination. Even if someone infringes on the utility model right, the proper rights holder cannot immediately take action to demand a stop to infringements or to claim damage. In order to take action to demand a stop to an infringement or to claim damage, the rights holder must request a "registrability report" that the JPO provides. This report contains an expert opinion on aspects such as the novelty and inventive step of the utility model.