Guru Harkrishan, the eighth Nanak, went to Delhi at the invitation of Raja Jai Singh and the sangat of Delhi. He was the honoured guest of the Raja and stayed in his bungalow. At that spot now stands Gurdwara Bangla Sahib.

While serving the victims of the epidemics of cholera and smallpox, the Guru himself contracted smallpox. He felt that his end was near. His Sikhs asked him who would guide them after him. Guru Harkrishan asked for five paise, and a coconut took them in his hand, waved it in the air thrice and said his last words, "Baba Bakala."

Soon after, on March 30, 1664 CE, the Guru departed from the world. His body was cremated on the bank of Jamuna river where Gurdwara Bala Sahib is located.

The last words of Guru Harkrishan clearly meant, "The next Guru is our Baba (grandfather) who resides at village Bakala (in Amritsar district)." Guru Tegh Bahadur was the grandfather of Guru Harkrishan and lived in his maternal village, Bakala, near Amritsar. As such there was really no doubt about the identity of the next Guru. However, the other pretenders to guruship, like Dhir Mal, grandson of Guru Hargobind, sought to take advantage of the situation and flocked to village Bakala. There thus, were 22 self-proclaimed gurus and each one claimed himself to be real Guru.

Knowing Guru Harkrishan's last words, as usual Sikhs from far and near came to have an audience with his successor at Bakala. But they were unable to discover the real one. These self-made gurus took Sikhs’ offerings by deceit or force. This scheme of things continued for some months.

A Gursikh, named Makhan Shah, was a trader in the Deccan and Masand of Gujrat area. Once, a ship full of his goods was sailing through the sea. There was a severe storm and Makhan Shah became fearful of the ship sinking. All efforts to save it seemed futile till Makhan Shah prayed, "O Nanak, save my sinking ship. I will offer 500 gold mohars." His prayer was granted and the ship reached shore safely.

In March 1665, Makhan Shah visited Bakala to deposit 500 gold mohars. He was surprised to find 22 self-made gurus. Who was the real Guru? To whom should he make the offering? He thought of a plan to trace the real Guru. He planned to offer two gold mohars to each self proclaimed Guru. The false one would readily accept them, whereas the true Guru would definetely ask for what had actually been promised.

Makhan Shah went to each of the self- proclaimed gurus and offered them two gold mohars each. They were all pleased at the sight of gold coins. Everyone praised himself to the skies, but no one asked for what had actually been promised. Makhan Shah recalls the following hymns from Guru Arjun's Sukhmani:

As long as a man deems himself good
No goodness can approach him
He who deems himself as of the lowly
Shall be esteemed as the highest of the High.

He was confident that none of them was the real Guru. He enquired if there was any other person who was known as a man-of-God. He was told that there is another man, called Tegh Bahadur who is a son of Guru Hargobind. He lives in silence, away from worldly affairs and makes no claims to the Guruship.

Makhan Shah went to Tegh Bahadur's house. He met Mata Gujri, his wife and requested an interview. She said, " He spends his time in worship and prayer all by himself. He does not like to be disturbed, but I shall go and ask him. If he agrees, I shall take you to him."

Makhan Shah was permitted to go in. He bowed before the Guru and placed two gold mohars before him as planned. The Guru opened his eyes, and saw two gold mohars before him. The Guru said: "Why are you breaking your promise? You made a vow of paying 500 gold mohars when your ship was sinking. But now you are offering only two."

Makhan Shah was filled with joy. He fell at the Guru's feet and placed 500 gold mohars before the Guru. Makhan Shah rushed to the top of the nearby house and shouted at the top of his voice : "Guru Ladho re Guru Ladho re"

"I have found the True Guru ! I have found the True Guru !" he proclaimed.
On hearing this, the Sikhs were overjoyed. There was a great rejoicing among them. They gathered at the Guru's door. The Guru came out of his place of meditation. A Gursikh from Delhi had brought five paise and a coconut which was offered to the Guru by Baba Gurditta, the grandson of Baba Buddha ji, as a mark of Guruship.
In this way Guru Tegh Bahadur was duly seated on Guru Nanak's throne on Monday, March 20, 1665 (Chet 23, 1772 BK) at the age of 44 years.