The Chinese translation is 真言; zhenyan; 'legitimate terms', the Japanese on'yomi studying with the Chinese getting shingon (that's also used as the appropriate title for that Shingon sect). In This method of assumed, all sounds are said to originate from "a". For esoteric Buddhism "a" has a Specific purpose mainly https://augustwmcqg.csublogs.com/32605887/rumored-buzz-on-mantra