Region Code (RC) is a DRM technique developed to allow movie studios to control DVD/Blu-ray releases according to the region, including content, release date, and price. RC is encoded in the DVD/Blu-ray video disc to restrict the area in which it can be played.

DVD Region Code
There are six different official region codes and 2 informal variations for DVDs as follows:

RC	REGION
1	United States, Canada, Bermuda, U.S. territories
2	Europe (except Russia, Ukraine, and Belarus), Middle East, Egypt, Japan, South Africa, Swaziland, Lesotho, Greenland
3	Southeast Asia, South Korea, Republic of China (Taiwan), Hong Kong, Macau
4	Mexico, Central America, South America, Oceania
5	India, Afghanistan, Ukraine, Belarus, Russia, Africa (except Egypt, South Africa, Swaziland, and Lesotho), Central and South Asia, Mongolia, North Korea
6	People's Republic of China
7	Reserved for future use
8	Special international venues (aircraft, cruise ships, etc.)

A commercial DVD player sold in a given place encoded with a specific region code is not allowed to play discs from a different region; however, region-free DVD players are also commercially available which can play discs of any region code.

Region Code Enhanced (RCE) is used on a handful of DVD discs (such as Warner Bros and Columbia DVDs) to prevent the playing of region 1 disc in another region, even if the disc is played in a region free player. The region 1 disc also contains a short video loop of a map of the world showing the regions, which is coded as region 2, 3, 4, 5, and 6. So that when the disc is played in a non-region 1 player, the player would play the material for its native region by default.

Blu-ray Region Code
Blu-ray adapts a much simpler region code system than DVD with only 3 regions as A, B, and C:

RC	REGION
A	North America, Central America, South America, Korea, Japan, Southeast Asia
B	Europe, Middle East, Africa, Australia, New Zealand
C	Russia, India, China, Rest of World

Passkey is able to remove RC and RCE for DVD/Blu-ray, and can make a Blu-ray player, like PowerDVD, Win DVD, TMT, etc., region-free so as to let users freely watch any DVD/Blu-ray content with no limit.