Made popular by Quake, WASD (also known as Was-duh, or WSAD) is a set of four keys on the left-hand side of a QWERTY or QWERTZ computer keyboard often used to control the player's movement in first-person/third-person (FPS/TPS) computer games. W/S control forward and backward and A/D control strafing left and right. These mimic the arrow keys, which are also commonly used for movement. A variation is W-A-X-D, used by people who are used to the arrows on the numeric keypad (which has the down arrow a line below the left/right arrows, instead of in between).
Many gamers consider WASD to be superior to the arrow keys for various reasons, including that more keys surround WASD than the arrow keys, allowing the player better access to more game commands, and the hand position for WASD being more ergonomic for right-handed players (one hand stays on the keyboard and the other on the mouse). However, many players who use the mouse with their left hand find WASD less ergonomic and prefer to use the arrow keys, and it is possible for a right-handed player to reach about half of the keyboard while still controlling a character with both the arrow keys and the mouse.
Other Variations
For players that have had a formal education in typing, now called "keyboarding," the WASD key combination is unnatural, counter-intuitive, and just plain silly as it forces your hand off the "home row" keys of FDSA. For these players the ESDF keys make more sense and don't force the player to put their hand in an unnatural position.
In addition to being the proper, natural typing position for your hand, if you move your hand temporarily to reach a difficult key you can easily return to the "home row" using your index finger's tactile sensitivity to find a small bump on the F key.
ESDF is the default configuration for several games; for instance Tribes 2.
In addition to the natural, proper key combination, ESDF, most games provide players the ability to misconfigure their keys however they like. Players with little or no typing experience might use some other key configuration that feels natural to their hunt and peck style of typing.
Also common is the "HJKL" (h=left, j=down, k=up and l=right) layout used in the Unix or generally the mainframe computer world. However, those mostly text-based applications use HJKL primarily because the keyboards for old terminals commonly either lacked arrow keys or placed them in an uncomfortable arrangement. vi is a popular text-based editor which uses the HJKL cursor movement layout. An example for a game that uses HJKL is the text-based "graphic" adventure NetHack.
Also similar is the "IJKL" layout, which is used by a growing number of DHTML/JavaScript games. These browser games cannot use the arrow keys because many browsers' windows will scroll if the arrow keys are used, thus hindering gameplay. IJKL, like WASD, are arranged in an ergonomic inverted T shape, and, since they are used by the right hand, adjustment is easy for people who commonly use the arrow keys.
Vaguely related is the "zxc" layout, used in many freeware games, and a common setup for emulation and older 2d gaming using a keyboard.
And finally, Belgian keyboards have AZERTY in place of QWERTY so this is a common usage among Belgian players that have taken no formal education in typing.
Trivia
- The PC version of Sega's Virtual On arcade game included a "Keyboard Real" mode for emulating the arcade hardware; this mode used a WASD and IJKL dual-cross to emulate the arcade version's twin joysticks.
- After being popularized by first-person shooters, WASD became more common in other computer game genres as well. Many of the games that have adopted this layout use a first-person or over-the-shoulder third-person perspective.