Hari-sauri das said that Srila Prabhupada chanted Harinam softly in Upamshu Japa. And so did Srila Bhaktisiddhanta, Srila Bhaktivinoda Thakura, and most of our Gaudiya Acharyas most of the time. So what is this Upamshu Harinam Japa and why is it so important? And why our Nityananda Gunjan should also be Upamshu.

Srimati Radha Herself covers Srila Raghunatha dasa Goswami with Her own sari when he is doing Harinam Japa and manasa-seva in his siddha-deha as Rati manjari in Radha Kund
Rupa Goswami on Upamshu Japa
In Bhakti-rasamrta-sindhu, Srila Rupa Gosvami describes sankirtana and japa as two distinct practices. Of the sixty-four limbs of bhakti-sadhana, number 32 is sankirtana (ucchair bhasha), “loud euphoric congregational chanting” and number 33 is japa, “very soft meditative chanting on beads.”
The specific japa verse in Bhakti-rasamrta-sindhu states: mantrasya su laghu uccharo japa ity abhidhiyate, “very soft muttering or utterance of the mantra is ACTUALLY CALLED JAPA.”
The mouth should open for the bare minimum needed to produce the sound of the Mantra. The lips should move the bare minumum required to pronounce the Mantra. And the tongue should vibrate for the bare minimum necessary to correctly pronounce each Name in the Mantra.
Of all the three, the tongue may move the most inside, the lips may move a little, but the mouth should still open for only the bare minimum needed. If someone looks at a person practicing Upamshu Japa, one may not be even able to figure out that he or she is producing any sound because the mouth is barely open with only a very little open space between the two lips.
Loud chanting may be called Vachika Japa but mostly falls under the practice of Kirtan. ... evam vrata sva-priya nama kirtaya (kirtan), jatanurago druta-chitta uccaiḥ (loudly)... (SB 11.2.40)
Upamshu Japa is the Only Real Japa
Here Srila Rupa Goswami’s use of the word “laghu” is very important. It means only the chanting practiced at a much lower volume and very softly is known as Japa. And this is the main characteristic and differentiating feature of the practice of Japa from Kirtan and other practices of Navadha Bhakti.
In correct upamshu japa, one mentally focuses on this very soft sound coming right out from the tip of the mouth and the meaning of the mantra which is the form of the Lord automatically manifests. During this practice, the japa sadhaka continues to fine tune one’s audible hearing to the slight movement of the mouth, lips, and tongue; and seek out the meaning of the Mantra with his or her mind by focusing on the sound of the Mantra coming out of the mouth.
Upamshu Japa Should Produce a Sound
The tongue may move inside more than the lips because the chanting should not be silent. It should be clearly audible to oneself even though it is very soft. The vocal chords in the throat should actually produce a very soft sound. It should not be soundless or even whispering.
Only then the sound of the mantra resonates within the mouth, throat, and the chest. So again to stress on the same point, it should not be totally silent and mental, there should clearly be a very soft audible sound heard by oneself.
In this way, the more one focuses on the sound coming out of the mouth while chanting very softly, the soft sound and the meaning of the sound merge by regular and continued practice.
The mind soon seeks out Sri Krishna’s sweet all-attractive form in Harinam Japa and Sri Nityananda’s merciful form in Gunjan, which spontaneously arise in the concentrated mind, heart, and soul by this very soft focused chanting and hearing.
Follow the Trail of the Sound of the Mantra Coming Out of Your Mouth and You Will End Up with the Form of the Lord in Front of You
This seeking out of the form of the Lord is achieved very effectively and successfully if one fully focuses one mind like a laser point on the sound of the Mantra coming out from just outside one’s mouth, right in front of it in the air, and just follow the trail of that sound in one’s mind.
Confusion Among Devotees
This is the real Upamshu Japa, which many devotees are not doing it correctly unfortunately. Either some of the devotees chant their japa very loudly trying to drown out the surrounding noises or voices and then strain their vocal chords so much that they find it very difficult to complete the daily quota of even 16 rounds.
Or some claim they have quickly completed their japa chanting mentally and silently at a very super-fast speed even though proper pronunciation of the Names mentally needs much more focus and concentration. Such mental chanting is only possible for very advanced sadhakas who have already practiced hearing a lot of audible upamshu japa and kirtan for many decades.
Hari Bhakti Vilasa on Upamshu Japa
From Yājñavalkya Samhitā:
śanair uccāryen mantram
iṣadiṣṭhau prachālayet
kiñcicchabdam svayam vidyād
upāṁśuḥ japaḥ smṛtaḥ (17.157)
“Very softly audible utterance of a Mantra with a murmuring sound with the bare minimum movement of one’s two lips is known as Upamshu Japa.”
upaṁśu japa yuktasya
tasmāt śataguṇo bhavet (17.159)
“Very soft Upamshu Japa is 100 times more powerful than loud Vachika Japa.”
Agreed Mansika Japa is 1000 times more powerful than Vachika Japa and is the deepest form of meditation. But it cannot be practiced by those who are impure in their mind and thoughts and also by those who have not sufficiently heard, pronounced, and meditated on the audible sound of the Mantra for many years.
Ajapa Japa is a bogus concept preached by the impersonalists because they want to make a show that they are chanting even if they are not. No one can chant more than Haridasa Thakura, 300,000 Names daily. But he never talked of Ajapa Japa. He only said that his body will never stop chanting even after his departure. He never gave the excuse of Ajapa Japa while living. In Bhakti, we believe in voluntary effort, only then the Lord reciprocates. ye yatha mam prapdyante...
Hence Upamshu Japa is the best middle path, awarding us 100 times the benefits and remembrance of Vachika Japa, while at the same not being so difficult and intangible to practice like silent Manasika Japa is, at least in the neophyte stage.
puṣṭi kāmair upāṁśukaḥ (17.163)
“All one’s desires are fulfilled if one chants the Mantra very softly but audibly with a slight movement of one’s lips and tongue.”
Haridasa Thakura Chanted Upamshu Japa
In Prema Vilasa Chp 24, it is mentioned:
tin lakho harinam
jape diva rati
lakha harinam mane
lakha kane sune
lakha nama uccha kori
kore sankirtane
“Namacharya Srila Haridasa Thakura became initiated by Lord Advaita Acharya and started chanting 300,000 Holy Names day and night. He chanted 100,000 Names audibly but very softly while hearing through his ears, 100,000 Names loudly in sankirtana, and 100,000 Names in his mind.”
So 200,000 of his daily Names were audible and only the remaining 100,000 were mental. One reason for this was that even though Srila Haridasa Thakura’s body was fully transcendental still as a part of his bhauma-lila it was not practically possible for his vocal chords to continuously produce sound for 24 hours daily.
Upamshu Japa is Recommended Over Mansik Japa
I would personally never recommend totally silent mental chanting unless one has chanted upamshu japa for hours upon hours daily for decades and realized the actual oneness between the audible sound of the Name and Form, Qualities, and Pastimes of the Lord. Some devotees practice manasika japa and call it upamshu japa. But upamshu chanting should never be totally silent. It should be construed as silent mental chanting which falls into its own third category of manasika japa.
Few Statements of Shastra and Acharyas About Upamshu Japa
The below quotes clearly state that our chanting should be audible or upamshu, not silent and only mental. They are many many more of such quotes but I am just presenting a few here just to establish the importance of Upamshu Japa.
Shrila Bhaktisiddhanta from an article in The Gaudiya, 1934:
“Those who have AUDIBLY chanted 100,000 Holy Names daily for fifteen or twenty years should know such things (intimate rasa katha of Radha Krishna). The beginners need not hear these topics or they will misunderstand.”
Letter by Shrila Bhaktisiddhanta to one of his disciples:
“One should call on the Lord through the AUDIBLE chanting of the Holy Names at all times. This will effectively remove all anarthas. Then atheistic people will not be able to shake you with their blasphemy.”
japato hari namani
sthane shata-gunaadhikah
aatmaanan cha punaaty-uccair-
japan srotrin-punaati cha
”Compared to one who is attached to chanting japa mentally, the person who performs audible chanting of the holy name is one hundred times better. Because he or she purifies others also.“ (Shri Naradiya Purana, Prahlada-vakya)
In Baul Sangita, Shrila Bhaktivinoda Thakura sings:
maner mala japbi jakhan
mana keno korbi bahya visarjana
mane mane bhajan jakhan hoy
prema uthle pade' bahya-
dehe vyapta ho'ye roy
abar dehe care, japay kore
dharay mala anukshana
1) My dear mind, by claiming that you chant japa within your mind, why do you cease the action of audibly chanting your japa? When one is truly qualified to perform bhajan within the mind and prema factually arises internally, then the external body also becomes pervaded by those symptoms. The body rocks and sways, while one incessantly turns their beads in chanting japa. But you don't possess any of these genuine symptoms externally. So why do you still persist with this facade of chanting mentally and cheating your ownself and others.”
To conclude with Harinam Chintamani 15.43:
nama spashta, sthira, o sukhakar haile, sri shyamsundarera rupa dhyana karibena. (bhaktivinoda bhashya)
“When you come to the point of chanting Harinam with clearly audible soft pronunciation, steadily without interruptions, and joyfully; please make an effort to meditate on the form of Sri Shyamsundara.”