Definition - What does Manasic Japa mean?
Manasic japa is one of three kinds of japa, mantra repetition. Manasic japa refers to the repetition of a mantra that happens mentally rather than aloud. The other kinds of japa are upanshu, which means "whispered," and vaikhari which means "audible" or "spoken."
Of the three kinds of japa, manasic japa is said to be the most challenging for beginners because it is more subtle. However, over time it becomes easier, and it is said that the yogi will enjoy the respite it brings from the way the mind is usually agitated by sensory distractions. Ultimately, manasic japa is thought of as the most powerful kind of japa.
Manasic japa is said to be ideal as a preparation for deep meditation.
Yogapedia explains Manasic Japa
Manasic japa, like other kinds of mantra yoga, is often recommended for yogis who have weak bodies or physical limitations and may struggle with the demands of Hatha yoga practices. It is said to be an easier, quicker and more certain way for such yogis to attain Self-realization.
Once all three types of japa are mastered by the yogi, some advise that a combination of all three should be practiced. The mind is said to respond well to the variety. For example, manasic japa may be practiced until the mind starts to wander, then the yogi can switch to vaikhari japa.
Traditionally, manasic japa is considered to be focused in the heart area, as opposed to the vaikhari, which is focused in the throat. For it to be effective, and have a power beyond that of simple introspection, it is suggested that the yogi know the power in the mantra that they are repeating. They should repeat the mantra with devotion, love and feeling. This mantra may be the name of a deity, or it may be a mantra, such as the Gayatri mantra, which is said to brighten the intellect.