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I Attended RubyWorld Conference 2025
I attended RubyWorld Conference 2025.
I had already visited Matsue and Izumo in May this year, so I was debating whether to go this time. However, I decided to attend because someone from my company was speaking, the NHK morning drama "Bakebake" had started, and I heard there would be no live stream or recording this time.
Day 0
I usually take a flight that arrives in Matsue in the evening, but I thought I'd try participating in the Ruby Hackathon at RWC for once, so I took a flight that arrived at Matsue Station around 12:00 PM. I left home at 6:00 AM. Matsue is far.
However, the train from Tokyo to Hamamatsucho was extremely crowded. It was during commuting hours, and it seemed like the Yamanote Line had stopped shortly before. I might have been better off taking the Tokaido Line to Shinagawa and then the Keikyu Line to the airport.
This time, an eel bento was provided to those who signed up as hackathon participants, so I had it as soon as I arrived at the venue. It was delicious.
The hackathon felt more like a "mokumoku-kai" (a quiet work session) than a typical hackathon. I spent my time researching IO::Buffer. Here is the result:
I'm still in the middle of investigating how IO::Buffer works, so I'll write a blog post once I'm finished.
In the evening, I attended the RubyWorld Conference 2025 Eve (Pre-party). It was held at the fisherman's hut "Mugiho". The food was great.
Day 1
Every year, there used to be RWC banners on the bridge leading to the venue, but there were none this year. I almost thought I had the wrong venue or date. I also seem to remember a banner at the venue itself in previous years, but that was missing too.
Smalruby Programming Koshien × WEB
It was great that they made Smalruby Koshien run on the browser using ruby.wasm.
Running in the browser seems good as it lowers the hurdle for participants.
Tea Ceremony
The traditional tea ceremony. I don't think it was held last year, but it has returned. It was delicious.
I recommend going right after the lunch break starts, as it's not very crowded.
Bento
It was very delicious.
Ruby Prize
Congratulations!
Mastering Scaling Organizations with Modular Monoliths
While the benefits of modular monolithization are hard to explain to the business side, by modularizing, you can identify the scope of impact when changing code. Therefore, by narrowing down RSpec execution to only that scope, you can reduce CI costs... translating that as a benefit might make it easier to communicate.
That was the kind of talk it was.
Accelerating DX with "The Key to Ruby Talent Development" — Thoroughly Explaining the Behind-the-Scenes of Training Know-how that Supports a Development Organization with Over 90% New Graduates
A talk about RIZAP's new graduate training. It seemed like quite intense training. I could really feel the RIZAP vibe.
Ruby Supporting Business Continuity Management
Securities Systems Built from Scratch with Ruby and Go: Good Points and Pain Points from Actual Development, and Lessons Learned
Case Study of Ruby Utilization in the Tokyo Gas Group's Earthquake Disaster Prevention System
In the first half, Ruby didn't come up at all, so I was listening while wondering if it was just used in some small part of the system. I was surprised to find out that the entire system was built with Ruby.
Ruby Supporting Dental DX - Development Case Study of Cloud Dental Practice Management System "Dentis"
A talk about the difficulties of dental care systems. Again, I was thinking "Ruby isn't coming up at all here either," and then the session ended due to time limits with almost no mention of it.
When I told Maki-san at the evening reception, "Please talk more about Ruby," it turns out the part he had to skip because he ran out of time had Ruby in it.
Ruby biz Grand prix 2025 Award Ceremony
It was a flashy event.
Reception
The sake was magnificent.
Rubyists obsessed with Shimanekko again this year.
I won a signed autograph board.
Day 2
Opening remarks by Maeda-san.
The lack of banners on the bridge and the absence of simultaneous streaming or recording was due to a lack of sponsors. It's a tough world.
30 Years of the Ruby Community
A talk about the Ruby community and the news that version 4.0 is coming out.
Tea Ceremony
The sweets were the same as on the first day.
Bento
It was very delicious.
Good Timing to Start PicoRuby
The World of Electronics Projects Opened by PicoRuby
Fundamental Technologies Supporting LLM Application Development in Ruby
How to Create "Today's Recommended Tests" - Test Extraction Algorithm for Ninja-style Testing
Ninja-style testing is great, isn't it? I've thought it was a good idea for a long time, but I've never been able to implement it.
Analyzing Taiwanese Like Code: A 3-Step Parsing Method for Pe̍h-ōe-jī Romanization using Ruby
Utilizing the Metaprogramming Ruby Exercise Book
Tangible Code: Understanding How Code Works by Seeing, Touching, and Changing It with Ruby
Closing
The next one will be held on December 3–4, 2026.
Bonus
When I closed the lid of my ThinkPad and opened it again, it had frozen, so I forced it to shut down by long-pressing the power button. When I restarted it, it wouldn't boot.
Windows booted properly, so it didn't seem like the SSD was broken.
When I selected an older kernel in GRUB during Linux startup, it started up fine. Apparently, the new kernel was the problem.
Let's Eat Oden on the Ichibata Electric Railway Oden Train after RWC! 2025 - Oden after RWC2025 -
Every year, there is an event called "Let's eat Yakiniku at Horikawa Local Beer Hall after RWC!", but it seems the venue couldn't be used this year, so an Oden train was held instead.
I went back to the hotel once to drop off my luggage and then walked to Matsue Shinjiko-Onsen Station while viewing Lake Shinji in the evening.
"Oden Train."
This is the real "Ruby on Rails." A two-car chartered train.
Oden.
There were several restroom breaks along the way.
I happened to sit next to Matsumoto-san. It was fun.
Sakaya
After the Oden train, it was still early, so I went to "Sakaya," which is known as a haunt for drunken Rubyists, and ate crab that had just come into season.
I left the place before the day changed and didn't drink too much, so I did well.
Day 3
After checking out of the hotel, I walked past Matsue Castle with Lake Shinji in sight. Since I had already climbed Matsue Castle in the spring of this year, I just passed by it this time...
Since I've been watching the morning drama "Bakebake," I visited the Lafcadio Hearn Memorial Museum. I ended up getting spoiled for the drama.
On the way to the station, I stopped by Karakoro Art Studio and saw the large underground vault.
Heading home on the 5 PM flight.
It took six hours to get home. I'm beat.
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