In the first poster of the film, the name has been written as 'Detective Byomkesh Bakshy!'.
The Bengali surname is written as 'Bakshi' in English.
When asked, the director said when translated into Hindi the spelling and pronunciation of a word might change. "The 'I' looks weaker at the end of the film's name. 'Y' on the other hand is a dynamic letter and so I changed it purely to get attention and attract people," Banerjee said.
Another change in the film is the use of the word 'detective' in the title as in the original story of Sharadindu Bandyopadhyay, the character never identified himself as a detective.
He maintained that he was merely a 'seeker of truth'.
"That was his way of defining his role. There was a conflict as he was never comfortable with being called detective," the director of films like 'LSD: Love, Sex Aur Dhokha' and 'Shanghai' said.
Promising surprise for everyone, he said even those who have read all the 32 stories of the original literature would be left stumped.
On the film, which is scheduled for release in April next year, Banerjee said his team had done a lot of research on the city's history and what had happened during the 1940s when the film is based.
"Kolkata at that point of time was in real danger of being bombed by the Japanese in 1943. There were air raids going on and the dockyard was bombed. There was fear as well excitement because Netaji Subhash Chandra Bose had taken support of the Japanese for a nationalist movement," he told reporters.
In contrast with the time period of the film, the music would be contemporary.
"I want people to go to Kolkata of the 1940s but with a brain of 2015 and so music is contemporary. This is a new cinematic relationship and the first thing I am trying to do," the director said.
The film's poster, he said, represents the illustrations of old Bengali pulp and adventure stories.
When asked what made him chose Sushant Singh Rajput, he said that he wanted someone who is understated and not larger than life.