Heiankyo Alien (known in the West by its Sega iteration, “Digger”) was a 1979 arcade hit in Japan, unique for having been created by students in the Theoretical Science Group of Tokyo University in 1979. In this 2002 interview originally featured in Chou Arcade, one of the original TSG student developers shares details and memories of its unusual development.

Heiankyo Alien @hg101

Heiankyo Alien – 2002 Developer Interview

originally featured in the book Chou Arcade

—To begin, please introduce yourself.

Tabata: I’m 43 (though I’ll be 44 in just a few days). I work for a company in heavy industry, designing and engineering boats and ships. Heiankyo Alien was programmed by several programmers working together, but there were two chief programmers, of which I was one.

—Please explain how you came to be in the Tokyo University’s TSG (Theoretical Science Group).

Tabata: In those days personal computers were starting to proliferate among the public, and I had been interested in them since high school. TSG was established in 1959. They had their own personal computer that they had built themselves, and I was invited to join the group by my senior, Kawagami. TSG didn’t only make games, either. From computer science to soldering to computer games, they were involved in a wide range of activities.

—Please tell us the events that led up to the creation of Heiankyo Alien.

Heiankyo Alien (MAME)

Tabata: The Invader Boom had just started to cool off, and at the time there was a column in the Weekly Asahi called “Dekigotorogy” (it still continues today actually, in book form). That column was running a feature called “In Search of the next Space Invaders”, where they went to computer clubs/groups at different colleges around the country, and solicited them for ideas about new games. For their second week, they came to Tokyo University and first visited the “Toudai PC Club” (a different group at Tokyo University), but the game idea they came up with was kind of uninspiring.

They then visited us at TSG, but we didn’t have any suitable ideas either. After they left, we turned to each other and said, “Ok, the article hasn’t been published yet. Let’s spend the next two days trying to come up with something!” We immediately held an emergency meeting on the first floor lobby of the student union building. It was led by Kawagami, who was my senior by one year, and at first we just came up with an idea. That idea was featured in the Weekly Asahi column, which was then read by the game company that eventually contacted us.

In any event, after the article came out, we felt we’d put so much time into this idea that it would be a waste not to program it. Since I owned an Apple II (which cost about $5000 then, I believe?), that task was given to me. However, what I finished was horribly unoptimized, and took 10 minutes to even load up. So Kawagami met me at the Higashi Nagasaki station on the Seibu Ikebukuro line, and I gave him the Apple II. He fixed the program, using the Apple II’s low resolution mode, which meant that the Aliens, Officers, and Holes were all represented by different colored blocks. This is the version we took and showed to the game company that had contacted us.

—What was the origin of the idea for Heiankyo Alien?

Tabata: Well, only Kawagami can probably explain this, since it was his idea originally, but I’ll do my best…

For our first idea, the player had to get rid of the cockroaches in his house by laying down cockroach traps and catching them that way (“snake” games were popular at the time, you see). However, setting the game in an open living room would have given the player too much freedom of movement, so we revised the playing field to look like a Go board. The movie Alien had just premiered in Japan and everyone was talking about it, and one of our programmers was determined to have us put an Alien in our game. So the cockroaches became Aliens, and the cockroach traps became pitfall traps. As for the “Go board” map, we talked about a number of different candidate cities: Sapporo, San Francisco, Chang’An, Kyoto… and what we ultimately decided on was Heiankyo (Old Kyoto). Then it was only natural that the player become a Kebiishi (old Heian policeman).

As it goes, the first title for the game was “Heiankyo Alien – Otoshiana Game” [[Heiankyo Alien — Pitfall Trap Game]]. These were mostly Kawagami’s ideas, by the way.

—How did the Heiankyo Alien development proceed, specifically? Was there any organizational structure?

Tabata: There was no clear structure, no. But as mentioned above, Kawagami and his senior by one year, Shimada, were like the project managers, and under them several people (all TSG students), including myself, did the programming and other development work. We worked in the Oda district, on the first floor of Denki Onkyou’s office.

Compared to what you’ve got today, our development environment was vastly inferior. It was before the time of in-circuit emulators, too. Our process was to have several of our programmers work on the code in z80 assembler, then someone would take what they’d written to the sole keyboard and type it out, assemble it, burn it onto a ROM, then finally insert that and see if it worked or not. We had to repeat that laborious process over and over… (tears)

—How long did it take to develop Heiankyo Alien?

Tabata: About 3 months. But there was a period of “training” during that time, so the actual work was done in a shorter period.

—A version of Heiankyo Alien for the PC was also announced in I/O magazine then. Was that developed by your group too?

Tabata: Yes. It was done by a different TSG member though, someone who was not on the arcade staff. The source code for Heiankyo Alien was structurally a thing of beauty, and quite new for its time, so it was copied and dispersed widely.

—Did the rules for Heiankyo Alien undergo any changes or refinements during the development? If there were other rules, what were they?

Tabata: The biggest one was the idea for a candy item. The kuchisake onna monster was very popular at the time, and part of that scary story is that if she’s chasing you, and you give her a piece of hard candy, then while she’s eating it you can get away. We wanted to use that idea and include hard candy in the game; if you grabbed it, all the aliens would stop moving temporarily. However, it would have complicated the controls, so we abandoned the idea midway through the development.

Another example was the time limit. At one point we realized that if your kebiishi just ran away or closed himself off, you could basically make the game go on forever. To prevent that we put in a timer that would cause a massive increase in the number of aliens and their speed if you took too long.

To keep the game from getting boring, we also modified the map a bit from a completely traditional Go board layout.

Also, when you die, and the sprite of the angel floats up off the screen—that was something that Denki Onkyou really pressed us for. It was only added at the very last minute.

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The Heiankyo Alien manga from the Game Arashi comic.

—What were some of the things you struggled with during development?

Tabata: There was one bug where if you added too many coins, the data of the coin counter would overflow into the VRAM, causing one of the walls of the town to disappear. When that happened, an alien could go through that wall, off-screen, and he’d be “wandering” through the RAM, eventually scrambling the data and causing the whole game to go berserk. We discovered that bug during a demo at the Amusement Machine Show event!

There was another bug where you’d start the game, but the kebiishi wouldn’t appear. He was actually off-screen.

—The use of two buttons in Heiankyo Alien (for digging and burying) was revolutionary for the arcades of the time. Were there any problems or resistance when it came to actually manufacturing such a brand new control layout?

Tabata: None in particular that I can remember.

—Tell us how you met and got connected with the game company Denki Onkyou.

Tabata: They contacted us after reading that Asahi Weekly article. Before that we had met with Namco, and been given a tour of the Namco offices. We even met the President of Namco. They never talked with us about turning Heiankyo Alien into a commercial game though. I think we met with Sega, too.

—And I’m assuming the arcade version of Heiankyo Alien produced by Denki Onkyou was entirely made by TSG members?

Tabata: Yes, that first arcade machine was developed entirely by us.

—Did you go to the location tests?

Tabata: We went to the Amusement Machine Show which was held in Harumi at that time. I remember how panicked we were when that bug appeared.

—Were there any amusing responses from the players trying it out for the first time?

Tabata: People were trying to see if there was a pattern to the Aliens’ movements, but they couldn’t figure it out. That got us some admiring comments, “Excellent! Just what I’d expect from a game developed by Tokyo University students!” In point of fact, the Aliens didn’t have any pattern or strategy; their movement is just random. Standing there silently incognito, watching people try to figure it out at game centers, I somehow got a taste of how Clark Kent must feel.

—What was the origin of the names for the different digging techniques, like the “Akihabara dig” and the “Arakawa dig”?

Tabata: The Akihabara one came from the fact that the layout of the holes in that technique resembled Akihabara station, which we were all familiar with. Arakawa was the name of one of the other programmers, he had his own technique too. Itou, who was the best Heiankyo player among us, invented the “Itou digging”, and Yoshisawa, who was from Nagano, called his move the “Nagano digging”. One of the more trivial ways to escape was called the “Inkyo dig” [[retirement digging]]. There were many more.

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Four digging techniques, clockwise from TL: Akihabara digging, Nagano digging, Arakawa digging, Retirement digging.

—How did Heiankyo Alien get picked up by the comic Game Center Arashi?

Tabata: I don’t believe they ever officially contacted us or anything, they just started using it on their own. Game Center Arashi was a magazine targeted at kids, so there weren’t many people around us who read it. Only insiders knew about it really.

—What did your friends and colleagues think when they found out you were the ones behind this game?

Tabata: Many older people we knew got it mixed up with Space Invaders. But there were a lot of kids who knew about it, those who were younger than us and still in secondary school. People were usually very surprised when they found out!

—Was anyone from TSG scouted by game developers?

Tabata: I don’t believe any individuals were scouted. We were approached and asked if we had any other ideas for games, though.

—What do you think of the various “remixes” of Heiankyo Alien, like Universal’s Space Panic?

Tabata: Opinions differed among the TSG members, but for me personally those imitators broadened the reach of Heiankyo Alien and shared it with others (albeit in a slightly different form), so to I was happy to see them.

—Were you involved in any other games besides Heiankyo Alien?

Tabata: None that were commercially produced, no.

—Please tell us what you’ve been up to since making Heiankyo Alien.

Tabata: After making Heiankyo Alien, TSG took on a lot of computer projects, not just games. That continued after we graduated, too. One of the developers of Heiankyo Alien founded his own company, Hyperware, and they’re still around today. They own the rights to Heiankyo Alien now.

As for me, I found normal employment and live your typical everyday life.

—Do you feel like the experience of making Heiankyo Alien was something that changed your life?

Tabata: Hmm, that’s a difficult question. We all thought it was a big deal at the time, but looking back on it now, I get the feeling it really hasn’t had that big an impact on my life.

However, I did learn a lot of things from programming it, things that occasionally came in handy later. In that sense I guess it did change my life.

—If you were to remake Heiankyo Alien today, what would you like to see?

Tabata: Hmm, maybe something where you wander around an actual virtual reality maze? Something where you could really experience the physical sensation of being eaten by an alien, and where you’d have to really dig—and get physically tired from it! But seeing the original game republished, as-is, would probably make me the most happy. It’s nostalgia.

—What do you think about games and the game industry today?

Tabata: It’s all so enormous now, I can only stand there and look on in amazement.

—Would you like to develop another game, if you had the opportunity?

Tabata: Games today are so big, they’re not the kind of thing I could get involved with. But if I have free time when I get older, I might like to program some simple games to keep my mind fresh and fend off senility.

—Please give a final word to all those readers of this book (many of whom probably played Heiankyo Alien back when it was in arcades!).

Tabata: Oh, is this a book for the middle-aged? (laughs) When you look up Heiankyo Alien on the internet today, it seems that many people still remember this game. I don’t know if that’s because of the merits of the game itself, or if the game merely registers occasionally in the memory of their youths. Either way, I hope it continues to be a happy memory.