 During World War II the demand for metal for the war effort resulted in many bells being melted down for scrap . As a result , those that survived are generally regarded as important historic artifacts . More than 70 @,@ 000 bells ( approximately 90 per cent of the bonshō then in existence ) were destroyed in this way . However , rapid production of bells during the post @-@ war period meant that by 1995 the number of temple bells in Japan had returned to pre @-@ war levels . 
