A kerf lock is provided for the retention of die cutting dies in die slots of a retaining board. A retaining system is also provided and includes a plurality of lock slots oriented substantially perpendicularly to a direction of insertion of a die cutting die. The lock slots have open faces to permit communication with the die slots. When the kerf lock is located within a lock slot it extends into the die slot until a die is inserted into the die slot. Upon initial insertion of a die into the die slot, the kerf lock compresses laterally. Once the die is completely inserted, the kerf lock exerts a normal force against the die in the direction of the die slot wall opposite the open face. An inserted die cutting die can thus be securely held within the die slot.