Ever since I watched Nirvana in Fire, I wanted some good strategy dramas/movies. The drama/movie should contain characters using cunning to outwit each other. It can be historical drama , modern drama or anything but the essential criteria is that it should have good cunning characters trying to outwit each other.  It can involve all the dirty politics and scheming. In fact if it is dark , it would be more welcoming.  I hope I would get suggestions. Thanking you all in advance for your help. :)    

You should definitely watch The Good Wife! It's really interesting to see how the characters outsmart each other!
Punch - Antihero main lead that sets out to take revenge against the man he helped bring to political power while fighting for his life.  I loved the balance of the male lead in his cunning (and often dirty) political strategy as well as him coming to grips with his own personal life.  Loved Kim Rae Won in this role, and the overall vibe is pretty dark and intense.

Empress Ki - A little more action, but this is all about court politics and characters trying to outwit one another to gain more power.  The female lead is smart, often smarter, than most of her male counterparts, and it's so much fun to watch her go up against the bad guys.  Primary focus is revenge, and a lot of it is done through their political system.  Less dark but still very emotionally tense.  The drama is longer, so you experience a lot more character growth.

Cruel City - Everyone has their own agenda, and this one is full of antiheroes.  It's hard to ignore the pull of Doctor's Son and his pure awesomeness, too.  Dark and gritty in feeling.

Bridal Mask - Lee Kang To works for the Japanese during their occupation of Korea - he works for them in hopes of earning enough money to support his family, but he's soon caught in the struggle for Korea's fight for independence and the Japanese determination to keep control.  Excellent casting and cinematography.  More based in action than cunning politics, but there's still quite a bit of politics with other main characters and cast members.  Darker, dramatic and melancholy in feel.
 
Six Flying Dragons. The beginning is a little slow (because the characters are still a little young), but then things get really good! It's mostly about politics, strategy and characters outsmarting one another.
(Ok, I just saw it's in your dropped list, but you only watched 1 episode. You really should continue it!)
Death Note (japanese movies)
Thnx to you all . @fanitha I didn't like the death note live version, the anime was much better. @joonie I heard good things about 6 flying dragons but the 1st episode put me off too much talking. @iIwyn , @smith, @pie I will check them out.
Endless Love
Sound of the Desert
Empresses in the Palace
Bodyguards and Assassins (Movie)