Wherever you looked in Japan in 2008, someone was bent over a tiny PlayStation Portable games console (PSP) – and that someone was probably playing Monster Hunter. From clusters of young people playing on groomed lawns outside universities to suited salarymen on packed trains, the game had friends, family and work colleagues banding together to track and fight gigantic fantasy creatures. You had a good chance of finding a game to join if you pulled out your PSP in any public place.

More than 40m Monster Hunter games, by Japanese developer Capcom, were sold between 2004 and 2017, but its success was confined almost entirely to its home country. Everything changed this year, though. When Monster Hunter World came out in January, it become not only the bestselling game in the series, but also the fastest selling game in Capcom’s history, selling 6m copies in less than a month. And much to the delight of long-time Monster Hunter players, it’s proved as popular in the US and Europe as it has in Japan.

Ryozo Tsujimoto has been the public face of Monster Hunter since the series began in 2008. Japanese corporate culture has a reputation for rigidity, but Ryozo is distinctly uncorporate. He wears leather jackets and fashionable boots and styles his hair more like a television personality than a business executive.

He is the son of Capcom’s founder and current Chairman, Kenzo Tsujimoto. His brother Haruhiro worked his way up the ranks to succeed their father as president and COO of the company. While Kenzo has spent the last two decades devoting his energies to his Napa Valley wine estate and Haruhiro has led Capcom’s business development, Ryozo is a born video-game developer. He has remained at the coalface of video-game design for his entire career; he never imagined doing anything else.

‘I’m just not a suit’ … Capcom’s Ryozo Tsujimoto.

“When I was growing up, Capcom made arcade machines,” says Ryozo. “In Japan, even now, there are arcades everywhere, one in every neighbourhood. I used to play at them a lot. I’m the kind of person who would never be good at a normal office work, so I always wanted to work in a creative industry. When I was looking for a job after graduating from university, I wanted to go into either games or toys … I’m just from that gaming generation. I was in primary school for [Nintendo’s] NES, high school for the SNES, and I’d grown up with games in a way that it made sense for me to want to work on them directly.”

As the third son in the Tsujimoto family, Ryozo did not face the same expectations as his brothers. “The older ones had more pressure to go into certain positions,” he says. “I had a bit more freedom – I wasn’t being lined up for something in the same way.”

I would never be good at a normal office work … I'm from the gaming generation Ryozo Tsujimoto

Free to pursue his passion, Ryozo started out as a planner – a Japanese role that is part game designer, part project manager – working on arcade games at his father’s company, in 1994. “At the time, arcade machines were the highest spec machines out there, and there was a huge gap between what you could do with arcade hardware and what you could do on the consoles of the time,” he says. “But over the years, consoles really closed the gap. It was possible to create really high-quality, leading-edge experiences on consoles, and they brought something new [in the form of] online and network connectivity that would allow us to create something really unique.”

The first Monster Hunter game, which came out on the PlayStation 2 in 2004, was one of three Capcom games that experimented with online connectivity. (The others were Auto Modellista and Resident Evil Outbreak.) Tsujimoto worked on all of them, handling the direction and planning of their online systems. “In some ways, Monster Hunter was the culmination of those games,” he says. “The more we did with online features, the more experience we gained – and the more we were able to implement better features … Monster Hunter was taking Capcom’s renowned, best-in-class action gameplay and putting it into an online cooperative environment.”

Ryozo Tsujimoto opens a Monster Hunter-themed Universal Studios Japan attraction in 2014. Photograph: Capcom/Universal Studios Japan

Cooperative play proved to be the secret of Monster Hunter’s immense success in Japan, which truly took off with the PSP’s Monster Hunter Freedom 2 in 2007, when Ryozo became the series producer. It’s a challenging game, but being able to face a giant dragon with three friends in tow meant you didn’t have to be the world’s most talented player to get by, and people of all ages and skills could play together. Japan’s urban infrastructure, where people are always in close proximity, was well-suited to a portable game that allowed people to play together. When I first interviewed Tsujimoto, in 2008, it was this social aspect that he thought was lacking in the west, where people are more likely to play with friends online in separate houses than together on a train.

There hasn’t been a fundamental social shift in the last decade that has enabled Monster Hunter to break through. Instead, it’s the technology – and Capcom’s approach – that’s changed. Monster Hunter World was the first game in the series that was built for a global audience, where previous games were released in Japan first and adapted for the rest of the world a year or two later. Because it’s a PlayStation 4 game, rather than a portable one, it doesn’t rely on close physical proximity to other players: you can play with people all over the world, much more easily than ever before. It helps that it’s extremely beautiful, with real-feeling natural environments and oddly biologically plausible fantasy creatures. But it also pares back some of the complexity that had developed over the years.

“Over the course of the series, we’ve built up a lot of features and systems,” says Tsujimoto, “and it got to the point with World where, even though we now have amazing tech at our disposal. I really wanted to step back to use that tech – not just to brush up what was there and add more to the design, but to rethink what makes Monster Hunter what it is and go back to its core design, but with the technology that lets us have a rich, vibrant, living ecosystem, not just a player and an enemy on a stage. You’re jumping into this living world where all the monsters, creatures and plants have their own presence and behaviours, and affect each other. It was a good opportunity to take stock and think about the future.”

Ryozo Tsujimoto at E3 2017 , with one of Monster Hunter’s trademark dragons.

It worked. Monster Hunter: World is a big hit, critically and commercially. The youngest of Kenzo Tsujimoto’s sons is now one of Capcom’s corporate officers, a position he probably never imagined having. As executive producer on Monster Hunter, he guides a team of hundreds to create new creatures, habitats and experiences for players. But he has not left behind his passion for creating video games.

“I absolutely still have an outlet for my creativity in my job,” Ryozo Tsujimoto insists. “A producer has a lot of responsibility for titles, and needs a great team or no game will come out. Hundreds of people work in the background on Monster Hunter, and I would never want to claim that it was [all] mine … [but] I work on the games from concept stage onwards to final stages of gameplay. I still get involved in gameplay aspects. I’m not just a suit.”