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Kijun Seo, Co-Founder & CEO at Planetarium – Interview Series



Kijun Seo is the Co-Founder & CEO at Planetarium, an open source gaming platform set to transform the longevity and the profit model of games. Rather than simply introducing open source model into games, they intend to make the games run forever through peer-to-peer networks and pioneer a new form of community-powered games.

Could you share the genesis story behind Planetarium?

I met my cofounder JC Kim in 2010, and while sharing an apartment together we worked on several side projects and start-up ideas in our early twenties. JC had moved on to start a successful customer loyalty service company, and I joined Nexon to develop KartRider Rush, which was one of the first 3D mobile racing games on the iPhone that went on to amass 10M downloads. Then I moved to San Francisco, joined Dropbox, and worked on real-time collaboration products there. But we kept in touch throughout the years.

In early 2018, as a side project we worked together on an HTML-based blockchain game called Nekoyume. We had this vision of creating an open source game backed on a blockchain, but we were surprised when it had gathered 30K signups in just a few months. Friendly investors approached us to build a team around our vision of fully decentralized gaming, and we decided to start the company with five other friends who were deeply interested in creating an open-source technology and content company.

Planetarium was one of the first companies from Asia to be selected for the Ubisoft Entrepreneurs Lab, a global start-up program fostered by Ubisoft. Could you discuss this experience on a personal level and how it has strengthened Planetarium?

As a personal level, I found a remarkable level of empathy and openness coming from a team of Ubisoft's size. When we first joined the lab, we were a small team of twelve developers working on both content and blockchain tech, and our product was still in the very early stages. It was pretty intimidating to showcase it in front of directors who worked on legendary games like the Assassin's Creed series. But we found out that not only they understood the potentials of blockchain technology, but knew how to nurture innovation, which can have a modest beginning.

The program offered expertise on wide ranging matters from game design to open source licensing, and it was also incredible to work on a proof of concept project with Ubisoft's Prototyping Team (Makers). They pushed us to use our technology in unique and unusual ways to explore new dynamics of play based on decentralization. We gained an invaluable ally during the program and a lasting relationship, where the Ubisoft Blockchain Initiative continues to operate a node for our game Nine Chronicles.

Instead of simply introducing open source into games, Planetarium intend’s to design games that operate forever through peer-to-peer networks. Could you explain this technology to our readers who may not be familiar with blockchain, or what peer-to-peer is?

In our perspective, blockchain and peer-to-peer technology can make a private online infrastructure into a public network with fair access for everyone. For instance, a game like World of Warcraft has millions of players living in a virtual world, but the world data is inaccessible to essentially everyone but Blizzard. If you wanted to count the number of players passing through Orgrimmar (capital of the Horde), implement new guild dynamics, or maybe stay in the previous world expansion, well, this is not possible without getting the permission of the company. Majority of online games are also shut down at some point even though there are active players, because they no longer monetize effectively for the company.

When the gaming infrastructure doesn't run on centralized servers, but lives on a distributed network of players, then it is possible for a game to live beyond the original company, and become a backbone for a rich, evolving, dynamic world. For example, the Bitcoin network powers a huge financial market, but no single company is responsible for the infrastructure. Therefore, we can expect it to be fair, and anyone can build new tools to interact with Bitcoin without permission, such as new marketplaces and wallets. Applying this to decentralized games, players have the freedom to mod and start a new network with like-minded people, which hasn't been possible for virtual online worlds powered by a single company. Could this really happen for online games? We think so!

What are some of the benefits for gamers of having peer-to-peer networks?

Perpetual world, open API and moddability, full player ownership of items, hack proof (data is secured by a gamer's cryptographic key, not stored on a centralized server, so if you can protect your private key it is not possible for someone to steal your account), decentralized economy backed by cryptocurrency.

What do developers need to know to design games for the Planetarium platform?

Designing a decentralized game can be challenging, but we've done the heavy legwork so that if you know how to create games for Unity, then you can easily onboard onto the Planetarium platform.

Libplanet our open source blockchain core written in C#, was designed so that developers can create complex blockchain applications fully on the Unity game engine. Blockchain state transition and game logic are all written in C#, so most of the code can be shared between the game client and blockchain backend.

We have extensive documentation for Libplanet, and also our reference game, Nine Chronicles is fully open sourced. Check out Nine Chronicles to learn more about the project structure, and we'd be happy to support you from our Discord community as well!

How can developers monetize these games?

Even with decentralization, monetization is pretty straightforward. If developers want to have microtransactions, sell seasonal updates, or deploy ads, these are all possible with the understanding that if monetization methods get too egregious, players have the option to opt-out and start an independent network. Unique items backed by a blockchain (NFTs) can be sold directly to the players, or developers can charge a special market fee for transaction.

Decentralized games can also have an in-game cryptocurrency, which can be sold early to crowdfund the game, and to share portions of your in-game economy with players and investors directly. In the beginning of the project, you design a distribution for the base cryptocurrency. For Nine Chronicles, we issued a base currency NCG (Nine Chronicles Gold), and sold 5% through a private and public presale, which covered our base costs for developing an early access version. Players can acquire NCG to make transactions on the game market, enjoy exclusive content, and “stake” to retrieve unique materials and resources which can be offered to other players.

What games are currently offered or being worked on?

Nine Chronicles is our flagship reference RPG, open sourced and in early access since October 2020. We have a very active community, and our team has great plans for its future!

Our strategy has always been to first, prove the technology and the market demand through our content, then to acquire select key partners to develop dedicated experiences that fully leverage the potentials of decentralized gaming.

We're discussing our next collaborative project with several partners, but the bar is high because we request from the partner a dedication to create a uniquely decentralized game. We have focused on building proof-of-concept projects with key partners, and some may become fully fleshed out in the future.

Is there anything else that you would like to share about Planetarium?

Decentralized gaming is still in the early stages, and we'd love to have your contributions, ideas, and partnerships to realize our vision of an open gaming infrastructure accessible by anyone. Come join us in this journey!

Check out Nine Chronicles in early access — it's a beautiful 2D idle RPG, and as a player, you can also mine the base currency NCG by providing your machine in the peer-to-peer network, or by contributing ideas and mods to the game. We also have grants and proposal programs to help your ideas come to life!

Thank you for the great interview, readers who wish to learn more should visit Planetarium.

Antoine Tardif is the CEO of, and has always had a love affair for games, and has a special fondness for anything Nintendo related.