If it’s a lengthy mantra, you might chant a part of it while you inhale and The remainder while you exhale. If it’s a brief mantra, you may repeat it while you inhale and exhale. The Chinese translation is 真言; zhenyan; 'real text', the Japanese on'yomi studying on the Chinese https://felixvuusr.tribunablog.com/mantra-an-overview-41164847