Why Do 2D Games Usually Go to the Right?

Taxonomy of Virtual Spaces

ROMchip Journal vol. 7 no. 1 includes a rare treat - a development essay by a Japanese developer that has been translated into English.

Author Hiromasa Iwasaki started in the game industry back at Hudson Soft in 1988 working on games for the PC Engine (TurboGrafx-16 here in the US). He served as director on the Turbo CD game Ys I & II (1989) and the Bomberman series game Atomic Punk (1990) for Game Boy, along with many other games that were never localized into English.

Lately, Iwasaki has been participating writing for dōjinshi publications, which are similar to amateur press publications. Dōjin circles are groups of creators who tend to publish together, usually around a particular theme or fandom, similar to amateur press associations. Japan's copyright laws make it easier for fans to create their own derviative small-press works based on popular characters from video games, comics, and animation and sell them in small quantities at dōjinshi conventions like Comiket (short for Comic Market). Most dōjin works are magazines and novels, but there is also a fair number of computer games (dōjin soft), board games, and card games as well.

On a side note, on my other blog, I have been researching about how some amateur dōjin circles became professional game design studios for board game and RPG publishers during the simulation game boom in Japan in the early 1980s. You can read about the Keio HQ Simulation Game Club in my translation discussion of Star Trek: The Invasion of Klingon Empire. You can also read the bio I wrote about Atsutoshi Okada, founder of the THQ dōjin circle and one of the most prolific simulation game designers of the era.

Legend Volume 7

Legend Volume 7 cover image (illustration by Hiroshi Aizawa)

Iwasaki has been writing for the Legend series of dōjin books. Volume 7 (shown above) features Iwasaki's essay about how and why early 2D games tend to have characters that move to the right, notably in "side-scrolling" games such as Moon Patrol and many others. This deals with the concept of Frame Mobility, how the screen appears to move (or not move) to show the player different parts of the gameworld.

Moon Patrol (1982, Irem)

Legend Volume 7 was available through booth.pm, a global dōjin marketplace, but is currently sold out. It was also sold through Comiket and other dōjinshi outlets in Japan, but is nearly impossible to access from the US... until now!

ROMchip logo

The game histories journal ROMchip funded a translation of Iwasaki's work into English and made arrangements to publish it in the vol. 7 no. 1 issue (July 2025). I recommend clicking over to that page to read it. Iwasaki writes on a number of subjects about game development, some of which is also published on his Colorful Pieces of Game blog.

Why Do 2D Games Usually Go to the Right?

My main interest is in his essay on early 2-D "side-scrolling" games and their tendency to have characters that appear to move toward the right side of the screen. The conventional wisdom is that this is a cultural norm for the English-speaking world. We read from left to right, therefore it feels natural to move from left to right. Others claim that the convention comes from old Western films, where the heroic gunfighter is shown on the left side of the screen so that his right hand is visible. Others claim that arcade game layouts often had a joystick on the left, therefore it was natural to start the player character on the left side of the screen. Still others claim it is a hard-wired part of our brain that left-to-right movement feels more "natural." Other claim that Super Mario Bros. did it, therefore it became standard. These arguments are echoed on The Escapist, Reddit, StackExchange, Resetera, and a study by Dr. Peter Walker of Lancaster University.

Few of these arguments question if there may be technical reasons why left-to-right motion became so prevalent.

Let's Standardize Terminology

Early on in Iwasaki's article, he has a quote that could sum up a lot of what my research means to accomplish.

Recently, I’ve had a few opportunities to talk about the history and technical aspects of games with university professors and graduate students, and I realized that if we don’t standardize terminology from the beginning, it can lead to confusion.

My Taxonomy of Virtual Spaces is an attempt to standardize the language we use to talk about virtual spaces. Instead of throwing around terms like "2.5-D," "top-down," or "isometric," let's agree upon and define what our terminology actually terms.

Iwasaki defines games in which the character moves left to right as Left Scrolling games. Conversely, characters move right to left in Right Scrolling games.

"Left Scrolling" sample image from the article

This makes sense in from the point of view of the graphics projected to the screen. What on the screen is "scrolling?" The background and environment, literally moving by much like unrolling a paper scroll. The environment and background movesto the left, giving the impression that the player character is moving to the right.

Iwasaki doesn't mention it, but this is a technique called induced movement.

Here is an example of induced movement that I use with my students. In the image above, we see the brave aviator Porco Rosso flying through the air in his seaplane. The plane is gently bobbing up and down and we see some secondary motion as the engine vibrates and Porco Rosso's scarf blows in the breeze. However, he doesn't seem to be going anywhere. There is no sense of motion and the aircraft feels static.

The addition of moving clouds provides induced movement to the aircraft. The stationary object appears to move right to left, in the opposite direction as the moving objects in the background. The plane is still smack in the middle of the image, but our brains read it as flying through the sky. This is the same way that side-scrolling games work.

Iwasaki also defines most vertically scrolling games as down scrolling (environment scrolls down the screen). I presume he would call a game like Downwell and up scrolling game.

Iwasaki admits that it is intuitive to think that a right scrolling should mean a game where the player character moves to the right as the environment scrolls. This make sense as we are used to thinking about games from the point of view of our avatar (the "self" in the logical interface between player and gameworld (adapted from terminology in "Nature and Origins of Virtual Environments: A Bibliographical Essay," 1991, Ellis)). Iwasaki had to change his thinking to focus on the thing that is actually scrolling: the environment.

Side-Scrolling Games

Iwasaki's discussion of side-scrolling games starts with the near-simultaneous arcade game developments of Scramble (Jan 1981, Konami) in Japan and Defender (Feb/Mar 1981, Williams) in the US. Scramble's Frame Mobility uses Auto-Scrolling in One Direction on the Horizontal Axis. The player's ship appears to be on an unstoppable march from left to right through the terrain. Defender's Frame Mobility uses Smooth-Scrolling in Two Directions on the Horizontal Axis (with a Mini-Map of the entire level). These innovations allowed players to explore expansive virtual worlds that were much larger than what a single screen could contain.

(Iwasaki also makes a brief mention of Sega's Bomber (1977) as a side-scrolling predecessor, but there is very little information about the game and it is unclear how impactful that title was. Coincidentally, I briefly mentioned Bomber in my last blog post and I haven't found out much about it either.) 

Star Blazer (1982, Broderbund)

Iwasaki quickly moves away from video arcade games with their powerful custom hardware and expensive price tags. Instead, he looks at how side-scrolling games were created on personal computers in the early 1980s. These computers needed to be general purpose, programmable, and affordable in the home and could not match the graphics seen in some arcade game hits. These would include games like Tony Suzuki's Star Blazer (see above), a Scramble-like left scrolling shooter that I put a lot of time into on my school's Apple ][ during lunch breaks. Your ship seems to speed left to right across a landscape filled with vital targets to destroy as enemy aircraft move right to left to attack.

"General Screen Coordinate System of a 2D Game Machine" image from the article

One issue that Iwasaki cites is the standard coordinate system used for placing sprites on the screen (interestingly, he has an aside about how Atari invented sprites, then called "motion objects," for Tank 8 and Sprint 2. According to Iwasaki, it was Texas Instruments that coined the term "sprite" when developing the TI-99 computer). As seen in Iwasaki's image above, the coordinates start at (0,0) in the upper left hand corner. The sprites also use this same coordinate system, where the (0,0) point on the sprite is in the upper left corner of the image.

As shown, sprites can easily be placed in the screen image as long as the upper left corner of the sprite is somewhere on the screen. It is simple to draw a sprite partially off the right edge of the screen and have it move left onto the screen in later frames (left scrolling). Problems come up if you try to draw a sprite off the left edge of the screen (right scrolling) as that would mean placing it into a negative coordinate. These values were often stored as unsigned integers with no ability to be placed in a negative position without special handling.

Technology and techniques evolved and it was possible to right scroll if needed (like in ˆJungle Hunt). But, it was inherently easier to left scroll rather than right scroll.

So, it is simple to draw sprites emerging from the right side of the screen and move left until they hit the left edge of the screen and disappear. The opposite is not as easy to accomplish. For a deep dive into this issue and other fun stories about early game development in Japan, read through the article at the link above.