A light gun peripheral built on the concepts of best-selling pre-video Nintendo toys from the 1970s, included as a pack-in with American consoles.
Japanese title: ファミリーコンピュターガン • Famicom Gun
U.S. release date: Oct. 1985
Japanese release date: July 1985
Alternate versions: Smash Bros series amiibo  Smash Bros series amiibo (Famicom color variant) 
Despite the fact that everyone always calls it a “light gun,” the Zapper didn’t work by firing light. Its technology instead worked by detecting light… and the particulars of its mechanisms help explain why it doesn’t work on modern televisions. While all NES games can run on original hardware, on 4K TVs, or through emulators, those that depend on the Zapper accessory have become increasingly difficult to use without complex workarounds.
The Zapper was inspired by Nintendo’s Kousenjuu SP target-shooting toys, a popular line of gadgets the company produced throughout the ’70s. But those guns, and the ones Nintendo equipped in its Laser Clay Shooting System arcade installations, truly were light guns: They fired narrow beams of light that would register a hit if they struck a sensor on the target. In the case of the simple Kosenjuu toys, you fired at light sensors built into the toys. With projection-based games like the original Duck Hunt installation, you fired a beam of light that was reflected from the wall against which the targets were projected to strike a sensor located on the projector apparatus.
However, the Zapper didn’t work along either of these principles. After all, what good would it do to shoot light beams at a television? A TV screen can’t register light input; it only projects. So rather than actively fire light, the Zapper passively read it. Nintendo built a light sensor inside the barrel of the gun—in other words, they put the target inside the pistol. This may seem an odd and backward approach to the problem, but it was a brilliant way to simulate arcade light gun tech with standard consumer-level televisions. Rather than force you to, say, position a sensor bar on top of your TV like later consoles would, the Zapper instead could read the TV display, at least on a primitive level.
The Zapper contained fairly basic technology—after all, it was first released in Japan in 1984, and it had to be affordable—so it couldn’t read every single pixel of the screen. But it could determine the relative position of simple targets, and it could distinguish between individual frames of 50 or 60MHz televisions, and that was enough to allow it to work.
When you pulled the Zapper’s trigger for a game like Hogan’s Alley or Duck Hunt, the NES would cycle through a few frames of specialized animation. This happened so quickly as to be nearly imperceptible—after all, the NES was running at the same 60 frames-per-second standard that modern game tech snobs demand. Three consecutive frames of animation amount to 1/20 of a second, meaning the Zapper’s mechanics passed by so quickly it almost seemed like you imagined them.
Pulling the Zapper’s trigger would cause several things to happen, depending on the game. Generally, it worked something like this: On the first frame, the screen flashed completely to black or white. On the second frame, solid white boxes replaced the sprites of the target graphics. (If you slow down a video of Duck Hunt, this becomes extremely visible: The ducks are replaced by rectangular white sprites after each shot.) Finally, on the third frame, the entire screen blanked entirely to black before returning to normal.
The overall visual effect of this sequence to the human eye is of a brief flash and an almost imperceptible hint of some kind of graphical weirdness, but to the Zapper those three frames provided important instructions. The first white frame acted as a sort of message to the Zapper saying, “Hey, something important is about to happen.” This solid white screen put the Zapper’s sensor into an active state, telling the software to watch for the next frame.The second frame, where targets become boxes, acted as the key frame in which the gun could determine a hit or a miss. If you were aiming directly at a target, the Zapper would see a white box dead center in its sights and therefore register a hit.
So, in Duck Hunt, for example, the screen blanks entirely to black for one frame once you pull the trigger. On the second frame, the duck sprites become white boxes. The third frame restores the background but not the ducks, as the game takes that frame cycle to calculate hits and misses. When the sprites return on the fourth frame, they reflect your success or failure: If you missed, the duck continued flying around, but if you’ve scored a hit, the sprite changes to that of a stunned duck plummeting to the ground.
In Hogan’s Alley, the cycle works a little differently, though the principle remain the same. The first frame after pulling the trigger is solid black, but the next two frames cycle through different sets of white boxes: One frame for each target on the screen. The game cross-checks to determine which frame, if any, registers a target dead-center in the gun’s sensor. If your direct hit registers during a frame highlighting a bad guy, you win; if you took aim at a civilian, though, you lose.
Meanwhile, Wild Gunman’s A mode doesn’t use this frame cycling at all—the game doesn’t judge for accuracy in the one-on-one shoot-outs, only speed. So long as you pull the trigger in time, you win.
The targeting frames with the white boxes were essential in any game with specific targets, as they reported to the Zapper’s sensor the accuracy of your aim. But just as important was the black initial frame, which served as an anti-cheat measure. The Zapper lacked the ability to properly resolve pixels or to determine exactly what the bright white at the center of the sensor was. It would have been entirely possible for players to trick the Zapper by simply pointing at a light bulb for the duration of the game, causing a bright object to sit at the center of the sensor. By introducing a single frame of pure black, though, Nintendo’s designers made that impossible; if the Zapper doesn’t read a blank screen after seeing a target, the game knows you’re cheating.
Unfortunately, this clever anti-cheat measure also prevents Zapper from working on modern televisions. The upscaling process that NES graphics have to undergo in order for the system’s 240p visuals to display on 720p or 1080p HDTVs introduces a moderate amount of lag even under the absolute best of circumstances. A dedicated upscaler like Micomsoft’s XRGB Mini adds a frame of lag; if you depend on a television’s built-in upscaler, you may have to deal with as many as four or five frames of added lag. And even if you’re playing with an HDMI-based system like the RetroUSB AVS, you still have to contend with the inherent lag of flat screen television display (the best of them still create a frame or two of lag).
One paltry frame or even two may not seem like a big deal, but Zapper games are programmed to expect certain signals at absolutely precise times. If the light gun doesn’t see the sequence of on-screen indicators it expects exactly within the 1/60 of a second interval it expects them, it ignores the data that does come in. Even a single frame of display delay means your game will function out of sync with the Zapper’s programming, rendering a game unplayable.
Nintendo has reprogrammed several Zapper games for Wii U Virtual Console, replacing the light gun with the motion-sensing Wii remote. It’s a welcome development, but you’re limited to playing the handful of Zapper games Nintendo has adapted. For light gun aficionados, whether on NES or later systems that used more sophisticated technology (such as the PlayStation’s GunCon), the only reliable solution is to keep a CRT television around for proper, lag-free shooting gameplay.
The caveats of light gun technology also mean the act of capturing Zapper footage for the screenshots in this book at the same quality level as that of standard games required significant workarounds. I record from a modified NES that outputs RGB video for an upscaler that converts the graphics to high definition, but I can’t run the system directly into the upscaler. My upscaler and HD television add about three frames of lag to the equation—nothing I can’t deal with for play, but more than enough to make Zapper gaming impossible. So, instead, the capture process goes like this: The NES sends video to a CRT, which allows me to use the light gun. The video then passes through the CRT, which is a high-end model that allows for both RGB input and passthrough output. From there, it feeds into the upscaler, from which it runs into a capture device that splits the signal to my computer and my HDTV for reference. This, of course, is ridiculous, especially to play a fairly forgettable game like Wild Gunman! But it perfectly embodies the fleeting nature of vintage games and the challenges involved in keeping classics alive as mainstream technology evolves and leaves them behind.
The Zapper, like many pieces of old game tech, was designed to create a clever illusion around a very specific type of technology—one that has not only been deprecated, but which is no longer manufactured anywhere in the world. Who knows, maybe CRT televisions will undergo a resurgence similar to that of vinyl records and suddenly go back into production again… but it seems unlikely.
So savor whatever time you can get with games like Duck Hunt. Sure, they’re simple, but someday it’ll be impossible to play them except through emulation. They’ll become victims of the march of technology. And that’s the kind of killer you can’t gun down in a simplistic law enforcement shooting range simulation.
Japanese Famicom Gun courtesy of Steven Lin