Blockchain technology records information to a ledger shared between thousands of nodes. In the technology’s purest form, those nodes are not controlled by any central authority, and information cannot be changed once written to the ledger. Because of the security and autonomy this technology offers (in theory at least), blockchains now underpin many popular cryptocurrencies such as Bitcoin. 

But as Kazuyuki Shudo, an associate professor at the Tokyo Institute of Technology, points out, «It has been nearly impossible to test improvements on real-world blockchain networks, because that would mean having to update the software of all the thousands of nodes on a network.»

In researching blockchains, Shudo and his colleagues searched for a simulator that would help them experiment with and improve the technology. But existing simulators were too hard to use and lacked the features the team wanted. Moreover, these simulators had apparently been created for specific research and were abandoned soon after that work was completed, because many of the tools the group found were no longer being updated.