What is Bak (Bhaag) Savari Utsavam
Bak (Bhaag) denotes a "Floral Garden" at Tirumala and it is known as Ananthacharya Thota. Swamy went in an "Apradakshina" (Circumbulation in Anti click wise direction) marg when he followed by Anathacharya with a crowbar.
That is the reason why this utsavam is known as Bhaag Savari Utsavam.
Lord surrendered himself to Ananthacharya
There is a story how the Lord surrendered himself to Ananthacharya, and it goes thus – Sri Ramanujacharya during his discourses at Srirangam told his disciples that Lord Venkateswara Swamy is very fond of flowers.
He questioned them whether anyone would go to Tirumala and perform Pushpa Kainkaryam (Adornment to Lord with flowers).
Ananthacharya stood up and declared that he is ready to serve the Lord of Seven Hills. Ananthacharya went to Tirumala, dug a big tank (koneru) and besides it planted several types of flowering plants.
Ananthacharya - Great Devotee
God always showers His blessings on His devotees. He surrenders Himself to His ardent devotees who always submit themselves in His seva.
There lived an ardent devotee to whom Lord Venkateswara becomes sevak. He is Ananthacharya. Ananthacharya planted many flowering plants on Tirumala Hills and named it with his Guru’s name. He was a great, dedicated bhakta of Lord Venkateswara
Chin got wounded
Lord Venkateswara swamy desired such devotee should be remembered by all bhaktas and got himself accidentally wounded on His Chin with a Iron Bar.
Bhakta Ananthacharya collected beautiful flowers daily from his flower garden, prepared floral garlands and performed pushpa kainkaryam to Lord Venkateswara Swamy. He named the water pond (koneru) as “Ramanuja Pushkarini” and the floral garden as ‘Ramanuja Udyanavanam’ (garden).
Swamy pondered how he can serve Ananthacharya who was serving Him with Pushpa Kainkaryam. One day Swamy and Devi, in disguise as Raja and Rani went to Ramanuja Udyanavanam (garden), plucked several flowers, smelt them and threw them on the ground and disappeared.
Next morning Ananthacharya visited Ramanuja Udyanavanam to gather flowers for pushpa kainkaryam to Swamy and found the plucked flowers lying on the ground. He gathered the remaining flowers for pushpa kainkaryam.
He urged Lord Venkateswara swamy to excuse him and that he will bring good garlands next day. But the next night also, Swamy and Lakshmi Devi repeated plucking and throwing the flowers on the ground in the garden..
*PC: Saptagiri Magazine
Plucking of flowers goes on
Next day Ananthacharya took small floral garlands and sought excuse from swamy stating that somebody was trying to spoil his pushpa kainkaryam to swamy.
Next night Ananthacharya hid behind a bush in the garden to catch the mischief creators.
As usual, Lord Venkateswara and His Consort entered the floral garden to pluck flowers. Bhakta Ananthacharya observed the couple plucking the flowers, decorating their heads and throwing them on the ground. Ananthacharya chased the couple.
Lord Venkateswara escaped and entered the temple but Devi could not escape. Ananthacharya tied the Rani to a tree with floral twine. He remained in the garden throughout that night.
Missing Idol of Lakshmi - Swamy Advised Priests to rescue
Next day, in the temple, the priests, after performing Suprabhatha Seva opened the doors of Garbhalaya (Sanctum Sanctorum) and found the missing Idol of Goddess Vakshasthala Lakshmi whom they worshipped as their Aaraadhya Daivam.
Then Swamy asked the priests not to feel perturbed about Goddess Lakshmi. Lord explained to them how He and goddess Lakshmi wanted to serve the great Bhaktha Ananthacharya but he misunderstood the divine couple and tied goddess to a tree in his Ramanuja udyanavanam (Garden).
Lord advised priests to rescue the goddess.
Priests visiting garden
Priests visited Ramanuja udyanavanam (Garden) with Nadaswaram and other musical instruments, explained to Ananthacharya the Leela of the divine couple in the disguise of Raja and Rani in the Floral Garden. But Ananthacharya insisted that the Raja and Rani tried to spoil his Pushpa kainkaryam to the Divine Couple.
But archakas repeated that poojas in garbhalaya (Sanctum Sanctorum) cannot be performed without Goddess Lakshmi. Ananthacharya replied that he will relieve goddess Lakshmi if she agrees with him as her own father.
Goddess Accepting Ananthacharya as her Father
Goddess Lakshmi, on the sincere and devotional request of the priests, agreed to accept Ananthacharya as her own father. Immediately, Bhaktha Ananthacharya fell prostrate before the feet of Goddess Lakshmi and cuffed his hands.
Goddess became a small idol and entered the cuffed hands of Ananthacharya. He and priests entered Lords Garbhalaya with the Idol of goddess where she entered the Vakshasthala of Lord Venkateswara swamy. This was followed by Kainkaryas to the divine couple.
Procession on next day to Chakra Snanam
In token of how Lord Venkateswara swamy with His Consort surrenders to his ardent Bhakthas, the Utsavamurties of Swamy with His two Consorts are taken to the Sannidhi of Ananthacharya in North Mada street at Tirumala on the next day of Chakrasnanam.
There, the descendants of Ananthacharya are honoured by priests on behalf of Lord Venkateswara Swamy and Naivedyams are offered to the utsavamurties.
After this ritual, swamy with His Consorts are taken to the Tirumala temple in an Anticlockwise direction (Apradakshinam way). Ananthacharya, the ardent devotee, is felicitated by Lord Venkateswara on this Bak (Bhag) Sawari Utsavam.