Question: Is it necessary to have a mantra for japa?

问题：有必要用一个咒语来念颂吗？

When the medieval Crusaders drove East for the holy wars, they witnessed worshippers praying with these japa malas, admired the technique, and brought the idea home to Europe as rosary.

他们看到礼拜者戴着念珠祷告着，欣赏他们的方法，并把这个理念和念珠带回了欧洲。