The Great Gambler（1979）

Jai (Amitabh Bachchan) is an expert gambler, and has been so as long as he can remember, and has never lost a game. These skills bring him to the attention of the underworld don Saxena (Utpal Dutt), who is interested in hiring him for winning large amounts of money from rich people and then influencing them into doing whatever he wants. Jai agrees to do so, and plays successfully, though unknowingly to entrap a patriotic Indian named Nath (Jagdish Raj) who works for the government. After losing large amounts of money, he is blackmailed into revealing the blueprints of a top-secret military laser weapon that hit any target within 50 miles. When the Indian police come to know of this, they assign the case to Inspector Vijay, who is asked to apprehend Jai at any cost. The only problem is that Inspector Vijay is Jai's look-alike, and is not at all a good gambler. After this Jai and Vijay's professional and personal lives get confusingly mixed up as Jai and Vijay both coincidentally are ...