This custom was transmitted to Japan by Kūkai (774–835), who Launched the Japanese Shingon (Japanese for Zhēnyán) mantra vehicle. Kūkai saw a mantra as a manifestation from the true character of reality and that is saturated with meaning. For Kūkai, a mantra is nothing however the speech with the Buddha https://titusyekrs.ka-blogs.com/79851846/little-known-facts-about-mantra