The period of validity of a registered trademark shall be ten years, counted from the date of approval of the registration. Where the trademark registrant intends to continue to use the registered trademark beyond the expiration of the period of validity, an application for renewal of the registration shall be made within six months before the said expiration. Where no application therefore has been filed within the said period, a grace period of six months may be allowed, yet extra fees shall be charged for the delay of renewal. If no application has been filed at the expiration the grace period, the registered trademark shall be cancelled. The period of validity of each renewal of registration shall be ten years.