This interview with Super Metroid and “Kaeru no tame ni kane wa naru” programmer Yasuhiko Fujii originally appeared in game shokunin volume 1. The first part of the interview looks back at Fujii’s programming and “hacking” origins, while the latter half covers his work at Intelligent Systems and includes design insights into Super Metroid and Kaeru. I’ve also appended an extra section of Super Metroid design trivia which Fujii originally posted to his mixi.jp site.

Yasuhiko Fujii – 2007 Developer Interview originally featured in the book “game shokunin vol. 1”

Early Days

—When did you get interested in games?

Fujii: When I was in grade school, I used to play a lot of Space Invaders, Breakout, and other early arcade games at the local neighborhood candy store and batting center. I was really obsessed with Pac Man and Xevious, too.

When I didn’t have money, I went to the department store. At that time, if you went to the electronics department, they had computers set up that you could freely use. My friends and I would spend hours there fiddling with those computers, drawing pictures on them, writing text, just messing around with all of them.

—So you were interested in computers first, before the Famicom?

Fujii: Yeah, I didn’t own a Famicom at this point. But my old school lent out computers, so one summer vacation I borrowed one and spent everyday completely absorbed in it. I also input some of those programs from magazines like Maikon BASIC. At the time I went to a very good high school, and they had Minikons and Hitachi Basic Master Level 3 computers set up too. I started studying machine language and assembler on these computers on my own.

Yasuhiko Fujii, programmer.

After that, I saved up money through my paper route and other little part-time jobs and purchased a PC-8801 mkII MR. The first commercial game software I played was The Black Onyx, and after that I played lots of other cRPGs like the Xanadu and Hydlide series. I enjoyed other genres too, playing and beating all different kinds of games.

Eventually my computer started acting funny, and I opened it up to investigate, taking out and testing each part one by one. This was a new way for me to enjoy computers. I fixed it myself, and in this way I learned about the nitty-gritty of hardware too, by tinkering and tearing everything apart. (laughs)

Later, “copy tools”—programs designed to remove the copy protection from floppy disk games—started to become popular. “How do these copy tools work…?”, I wondered, and I started to get interested in them, and I eventually started doing my own disassembly. But I was really interested in both hardware and software, so I worked on other projects too, like building my own radio.

—It’s quite amazing that you taught yourself all this on your own!

Fujii: I had enrolled in the electronics program at my technical high school, and for my elective in my third year, I also created and designed my own computer from scratch (from the PCB). It used a z80 CPU. There was no display though, so it could only display the results of calculations and so forth using LEDs. Around this time I also bought a copy of DOS, and built my own (commercial) computer too.

If I had to say, I was really more a hardware guy. Microsoft’s DOS had just gone on sale in Japan, and I was especially interested in operating systems. I really wanted to know how they had made it.

—In other words, it sounds like you weren’t originally that interested in making games.

Fujii: Yes. After DOS left such an impression on me, I had decided I wanted to work in that field, and I originally thought I would try and get hired by Microsoft. However, my teacher discouraged me, as he didn’t think there was much work like that in Japan yet. No one in Japan really knew much about operating systems then, even my teacher.

—What did you do after graduating from high school?

Fujii: I figured I should probably focus on my studies a bit more, so I enrolled a 3-year technical college program. By this time, the X68000 was out and very popular, and I played that a lot. My main PC at school was the PC-9801 VM, and I took classes on the 8086 CPU and the C programming language. I also continued my hobby of building computers from scratch, from schematic blueprints. And of course I kept playing video games. I frontloaded my first year at college with a ton of classes, so by my second year, I had lots of free time. I spent a lot it bowling with my friends and playing the UFO catchers at game centers, where I became obsessed with collecting plushie prizes (nuigurumi).

Today Intelligent Systems is popularly known for the long-running Fire Emblem franchise, but their 8/16-bit works also include classics like Metroid, the Super Scope “Battle Clash” games, and Panel de Pon (rebranded Tetris Attack), which Fujii’s wife worked on. Fujii himself only worked on two games with Intelligent Systems before leaving the company.

Joining Intelligent Systems

—When did you decide to work in the game industry, then?

Fujii: It was in my second year of college. I had been moved in my life by playing games, and I thought I wanted to return that experience to others and create games that would move them. I think that was my biggest motivation. However, in my case, I had focused entirely on learning about the technical side of programming and computers, and if you had asked me then to do “game design” I wouldn’t have known where to begin. I was fairly confident in my programming skills, though, so ultimately I decided to work for Intelligent Systems.

—What was the reason you chose them?

Fujii: Well, I apologize if this is a bad answer, but the simple reason was that they were within biking distance from my house. (laughs)

I first heard of Intelligent Systems in my third year of college during the traditional recruitment season. I didn’t even know they were making Famicom games specifically, until I went to visit their offices. I never really had that much interest in the Famicom, you see. It was only after I visited them that I even imagined it, “Ok, yeah, I could give Famicom programming a try.”

Because I knew nothing beforehand about Intelligent Systems, I originally meant to visit their offices just to get a feel for the place, but when I got there, they suddenly asked me to take a test! I hadn’t prepared at all, so I was really taken off-guard. After taking the test, as soon as I got home the phone rang, and it was Intelligent Systems, asking me to join, and I accepted.

—Ahead of the curve with your class credits, and hired by a company before graduation… it sounds like you were living the ideal college life!

Fujii: After that, I took a part-time job at a computer rental store. Like the video and CD rental stores of today, it was a place where you could rent computer games.

I had actually been going to that rental store for a long time, because I would go there after class in high school. At that shop, one of the employees was the same person who made the famous copy tool “The Filemaster”. Over time we became friends, and he would let me try out new versions of his copy tool, which I then used to analyze different games. We’d get really excited talking and sharing our efforts: “I tried to crack this one, but I just couldn’t figure it out!” (laughs) In those days, you had a new versions of copy tools coming out practically every week.

—Hah, so after working at this store all day, you’d get home to try and crack the games?!

Fujii: There definitely were a lot of people who did that. In my case, though, I had zero interest in trying to make money or sell blackmarket versions. I was driven by a simple, honest curiosity about how these things worked—a technician’s spirit more than anything else. And while there were people who used the copy tools for ill gain, there were many others like me who saw it as a great way to increase your skills and knowledge. I remember how people who used to mess around with disassembly were called “hackers” in those days… honestly, I had no idea what the hell that English word meant, but I sure thought it sounded cool.

Nintendo’s 1992 commercial for Kaeru.

Making “kaeru no tame ni kane wa naru”

—What was the first game you worked on at Intelligent Systems?

Fujii: “Kaeru no tame ni kane wa naru” (“The frog for whom the bell tolls”), for the Gameboy. I mainly programmed the enemy algorithms.

—”Kaeru…” was a very simple and quite fun game, yet the title sure is a weird one.

Fujii: In the beginning of the development, it was called “Paraparesu”,1 but Nintendo’s President Hiroshi Yamauchi said that was no good, and we changed the title. The new name was so weird, I honestly wondered if this was a good idea, but once Kaeru was finished and I saw the commercials Nintendo had made for it on TV, it was extremely gratifying to see something I made given the royal treatment like that.

A large portion of the programming for Kaeru was actually completed when I was still in college, on the summer vacation of my third year. An employee from Intelligent Systems handed me the technical programming manual for the Gameboy and said “study this for a week.” After that I told him I had mostly gotten the hang of it, and he came back with the planning documents for Kaeru and said, “Ok, now make this!” The map scrolling routines were completed entirely in my spare time that summer.

—Wow, after just one week to review the Gameboy specs, you were able to do all that…?

Fujii: Well, if we’re just talking about programming, I was confident in my abilities then. It was game design itself that I didn’t understand very well. On that note, Intelligent Systems told me to study The Legend of Zelda, which I kept beside my desk the whole time I worked. I originally made Kaeru to be more of an RPG like The Legend of Zelda, but I realized that copying it wouldn’t be very interesting, so midway through I simplified the battle system. I actually remade the whole system 3 times, partly because Super Mario Club (Nintendo’s in-house playtesting/debugging group) gave the first version a bad review. After I graduated and became an official full-time employee at Intelligent Systems, I managed to finish Kaeru with a lot of help and support from one of the senior employees there.

—On the ending screen you’re credited as “FOE Programmer”, but what does FOE stand for?

The artfully drawn kanji script made Kaeru standout, at a time when many Japanese people ignored RPG style games because the hiragana scripts, which most 8-bit games used to save memory, were annoying to read.

Fujii: It’s just the section of the game I coded, and the “E” stands for ENEMY. We wrote it that way just to make it fit on the Gameboy’s tiny screen.

—Yeah, I remember being impressed by how you managed to include actual kanji characters for the dialogue, despite the Gameboy’s small screen and resolution.

Fujii: For the kanji in Kaeru, I extracted the kanji data from a PC rom file, then converted it from 16×16 to a Gameboy-friendly 8×8 size using a “Kanji Converter” program I made myself. When one of our designers saw that program, he was really impressed, and wanted to use it to make other graphics from text symbols.

Super Metroid

—After Kaeru was completed, you switched to the development of Super Metroid.

Fujii: Yeah. The person who wrote the scenario for Kaeru also worked on Super Metroid, and through that connection I got invited to work as a programer on it. There were seven programmers in total, and I primarily worked on the boss and enemies: their sprites, hitboxes, etc. Samus alone took so much data to animate and draw, there was a single programmer dedicated just to working on her—that’s how big and involved the Super Metroid development was.

There were a huge number of enemies, too, and one day I had an insight about that: I should make a “Programming Tool” for the designers, and I did. It allowed the designers to input their graphics/sprite data directly into the tool, and it would automatically convert that into actual source code, complete with collision detection data. There were so many designers working on Super Metroid, and everyone had their own way of doing things… I knew if they each did their own thing it would be a huge problem down the road. So I developed this tool to help set some rules and unify their process.

Each enemy still has a completely different movement pattern, and the boss fights had to be designed around fair, “winnable” patterns, so even with a tool like this, Super Metroid still required an imposing amount of work.

—With so much data to create, I imagine Super Metroid had a very long development?

Fujii: Yeah, it took about 3 years. It was a joint venture between Nintendo and Intelligent Systems, with Nintendo doing the planning and design, and we did all the programming. In the final push before the deadline, though, we all worked together at Nintendo’s main office and pulled many consecutive all-nighters there.

It was during that time that I heard a strange “fuu, fuu” sound coming from the office beside mine. I walked over to see what in the world was making this sound, and to my surprise I saw President Yamauchi standing there, diligently practicing his shakuhachi flute. (laughs) Part of my shock was realizing that the President’s office was right next door to ours, and that only a thing wall divided us. It was certainly surprising to hear the sound of a shakuhachi in the office like that, but even more shocking, was that I would often see the President walking up and down the halls of the office there in his momohiki (tight-fitting, traditional Japanese trousers), too…

As Fujii describes above, the large number of enemies in Super Metroid required the use of new development tools to unify the design work. A few enemies never made it, but are included in the ROM (as documented over at tcrf): clockwise from top left, they are “Bang”, “Reflect”, and “Stoke”.

—Since you had been entrusted with one of Nintendo’s flagship titles, did you feel any mental pressure while developing Super Metroid? Like, “if we make a half-assed game and it flops, I’m in big trouble” kind of thing?

Fujii: No, not particularly. I personally had not played and knew nothing about the original Famicom Metroid, and only after I was assigned the job of main programmer did I play it for the first time. My first impression, to be honest, was “So… why do people like this, exactly…?” But as I played further, I started to understand the appeal of discovering all these hidden passages and secrets, and I came around.

—That certainly is one of the draws of Super Metroid, but I wanted to ask about the final escape scene, where the Dachora and Etecoon animals (who elsewhere help Samus out) can be saved by Samus at the end. I loved that part. Who came up with that idea?

Fujii: That was something a different programmer came up with on his own. And if you save them, when the planet explodes there’s some extra graphics showing them successfully escape too.

—Were there any scenes in Super Metroid that were your idea(s)?

The little Evir enemies before the Draygon fight trace the words “Keiko Love”. It’s a little hard to make out, but you can identify some of the larger letters if you look closely.

Fujii: Actually, before the fight with Draygon, the boss of Maridia, there’s a group of Evir enemies that do a little “dance”. Their movements actually trace out the letters of a phrase in English, “Keiko Love”! Keiko was the name of a girl I was dating at the time. I was busy with work all the time and couldn’t see her much, so at night while everyone at the office sleeping, I stole a moment and snuck that code in!

That little Evir dance wasn’t written in the planning documents anywhere, so I remember my heart beating fast as I coded it, with the worry of it being discovered… but in the end, no one ever found it out. Now isn’t that a romantic story? (laughs)

additional Super Metroid trivia from Yasuhiko Fujii

originally shared on his mixi.jp site

Now that the “statue of limitations” has passed on Super Metroid, I can share some fun behind-the-scenes facts with you about it!

First, did you know we had different development codenames for the bosses?! For example…

Spore Spawn –> Eriko Flower

Phantoon –> Obakeen2

Draygon –> Dankoon3 (laughs)

Originally, Draygon was much more grotesque. He actually looked too gross and realistic, so the director made us revise him, and that’s where he ended up. Even then, I was surprised how far they were allowed to take it. The programming for Draygon, of course, was done by me. (laughs)

The “Eriko Flower” name is a little weird… there was this talent named Eriko Kusuta, and we thought the Spore Spawn design looked like kusudama, so kusudama became kusuda, then kusuda eriko, then Eriko Flower… the person who made all these names up was the scenario writer for Kaeru. He was a very “unique” individual. (laughs)

The ability to kill Draygon with the Grapple Beam (by firing at a turret and electrocuting him), was part of our overall design philosophy for the bosses: that they all needed to have a weakness somewhere. With that in mind, we wanted to add something surprising for players. It was also done for people who keep dying to that annoying “W” swoop attack of his… we wanted it to be this eye-opening moment, like “whoa, you can do that?”