He was a pioneer of political science and economics. A man who won battles using his brain. He helped establish the Mauryan Empire. But before he helped Chandragupta take the throne, there's a legend that says it was all part of a revenge plot. A tale of impressive planning by the great Chanakya.
Source:
Sandesh
There are two different versions of the story. Believe whichever one you want to, it still makes for the perfect revenge against an undeserving & corrupt king.
1. A king banished him for being ugly, so Chanakya got his revenge by overthrowing him with Chandragupta.
This is the Buddhist version. When Chanakya was a kid, he had canine teeth. It was a mark of royalty, one day he was meant to rule. His mother was always scared that he would ignore her after getting the throne. For his mother's satisfaction, he broke his teeth.
A grown up Chanakya went to attend an alms-giving ceremony held by King Dhanananda at Pushpapura. Chanakya also had crooked feet. His appearance was not pleasing to Dhanananda's eyes, so he had Chanakya banished.
Source:
twitter
An angry Chanakya vowed revenge and managed to evade arrest by escaping to the jungle. He somehow managed to befriend Pabbata, Dhanananda's son. While in the forest, he saw a boy play-acting with his friends.
The boy pretended to be king, presiding over a trial of some robbers, where he orders their limbs to be cut off, only to magically heal them later. That boy was Chandragupta. Chanakya took him under his wing.
Source:
youtube
He saw Pabbata and Chandragupta as options for replacing Dhanananda. So he decided to test them. One day when Chandragupta was sleeping, he asked Pabbata to remove Chandragupta's woolen thread without waking him. Pabbata was unsuccessful. The next night, Chandragupta was given the same task. He succeeded by cutting off Pabbata's head and retrieving the thread and became the chosen one.
It took years to prepare an army for an invasion. They attacked Dhanananda's capital - Pataliputra. But were defeated. They managed to evade capture and one day, under disguise, while wandering the city, they overheard a mother scold her child for eating his cake from the center and wasting the edges.
Source:
punjabkesari
She compared that to Chandragupta's attack in the sense that he did not capture the neighbouring villages and directly attacked the core. On learning their lesson, they took the right course and captured areas around the capital city first. Soon they marched on to Pataliputra and overthrew Dhanananda.
Chandragupta was appointed king and Chanakya persuaded a fisherman to reveal the location of Dhanananda's treasury and had the fisherman killed. His revenge was complete.
2. A king's servant disrespected Chanakya and threw him out, so he came back with Chandragupta to dethrone him.
According to the Jains, the monks claimed Chanakya was born to be the power behind a throne as he had a full set of teeth. His father, fearing that he might get arrogant broke his teeth. Chanakya, married a Brahmin woman, who was often ridiculed for marrying a poor man.
Chanakya had heard rumours of Dhanananda being generous towards Brahmins. So, seeking donation, he went to visit him. While waiting for the king, he sat on his throne. A servant offered him a different seat. But Chanakya simply placed his water pot on it and did not leave the throne. More offers of other seats were met by more objects being placed on them.
Source:
youngisthan
Angry, the servant kicked him out. Chanakya felt insulted. He knew of the prophecy the monks had made and plotted his revenge. He helped a pregnant lady in the forest on the condition that her son would belong to him. That kid was Chandragupta. Chandragupta's conviction as king while playing his friends proved his worth to Chanakya.
The rest of the story is pretty similar.
Source:
newsdogshare
Their first attempt of taking Pataliputra was thwarted. In this version, they overheard the mother scolding her son for putting his finger in the middle of some hot porridge. She said he should have started with the cooler areas around the edges and compared it to Chandragupta's failed plot.
This time they made allies nearby and invaded villages around the capital. Soon a successful siege on Pataliputra saw Chandragupta on the throne and Dhanananda dead.

There are two more versions which aren't as reliable though.

1. An impostor king insulted Chanakya, so he used magic to kill him.
According to the Kashmiri version, 3 disciples of a sage arrive for gurudakshina at Dhanananda's doorstep only to find out that he's dead. One of them takes form in Dhanananda's body and grants the other disciple a huge donation. Shakatala, the minister, realised it but he was locked up, along with his 100 sons. All his kids die of starvation since food for only man was served everyday.
Source:
4remedy
Shakatala meets Chanakya after being released. He promises him that the king would give Chanakya 1000 gold coins. However, when they reach the court, he arranges for someone else to get it. Shakatala convinces an angry Chanakya that it was the king's fault and asks him to use magic to kill the king. He agrees and and the fake Dhanananda died in 7 days.
2. A king removed him from his court so Chanakya formed alliances to overthrow him.
This, theMudrarakshasa version, is the least likely version of the truth. In this version, Chanakya is removed from a seat at the kingdom and he plans to take revenge by forming alliances with many armies. With Chandragupta by his side he conquered Pataliputra.
None of these theories are proven. But they have been written about. Regardless, they make for a fascinating read.
Disclaimer: We do not claim any of the theories to be true. This article is merely meant to inform that these theories exist, not endorse them.