Ruby is my favorite programming language, and I was excited to attend Japan’s RubyKaigi, the oldest and largest Ruby conference. It was my first trip to Japan, and I was nervous about going there only knowing a few Japanese words. Thankfully, it was surprisingly easy to travel around as most signs were in English as well as Japanese, and Japanese people were quick to help me when I looked totally lost.

September in Japan

To make my first trip to Japan more exciting, a typhoon hit Japan the day before the conference started. I was lucky to avoid canceled flights and only dealt with the train taking twice as long as normal. The RubyKaigi organizers wisely decided it is too risky to have a conference in Japan during typhoon season, so next year’s conference will be held in May instead.


I am continually impressed by the niceness of the Ruby community. The Ruby community motto is MINASWAN: Matz (the creator of Ruby) is nice and so we are nice. As a woman attending a technical conference, I am usually in the minority, and I was even more in the minority at RubyKaigi since I was also a foreigner. Everyone was nice to me and made me feel welcome at the conference. Many of talks were in Japanese, but they offered live translations through a receiver. The slides were also in English, so they truly put in the effort to make foreigners welcome.

The content of RubyKaigi is highly technical, and almost every talk included code. The final keynote discussed ways to achieve the ambitious goal of improving Ruby performance by three times in the next major version release. Vladimir Makarov talked in depth about his efforts towards this goal in developing RTL (Register Transfer Language) Virtual Machine instructions and JIT (Just-in-time) compilation for Ruby. His talk was one of the most technical talks, and I understood very little of it since I never learned C and haven’t studied compilers since college. Even without understanding all of his talk, I appreciated the challenges to improve Ruby performance by three times. The design of the Ruby programming language has been focused on productivity and the joy of programming, but performance has become a priority now. I hope that they will make significant progress towards their lofty goal so that I can program in my favorite language without having to be concerned about its performance.

Favorite Talks

Do Androids Dream of Electronic Dance Music? Julian Cheal & Eric Weinstein

Although this project only had 5% Ruby code, I enjoyed hearing the music they generated through machine learning.

Mapping your world with Ruby: Mat Schaffer

The Safecast organization was created after 2011 tsunami in Japan to collect and share information on environmental radiation. This talk was more impactful to be given near the site where the atomic bomb was dropped in Hiroshima.

Compiling Ruby: Kevin Deisz

I learned a lot about how the Ruby compiler works at RubyKaigi. This talk showed interesting examples of how to hack the Ruby compilation process to create macros and perform type checking.

Memory Fragmentation and Bloat in Ruby: Nate Berkopec

This was one of the more practical talks I attended with good tips on how to prevent and fix memory issues with Ruby. He’s got plenty of similar helpful tips on his blog.


I had a great time at RubyKaigi and enjoyed my first trip to Japan. I did some sightseeing while in Japan, including kayaking through the Torii at Itsukushima Shrine near Hiroshima, one of the three most scenic views in Japan. Next year’s RubyKaigi is in Sendai, Japan, near one of the other most scenic views, the pine-clad islands of Matsushima. I would love to attend RubyKaigi again and see all the three most scenic views in Japan!