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Taro Hayashi's Killer Whale

The Killer Whale, a split keyboard with versatile thumb cluster options by Taro Hayashi, is making its rounds in the Japanese community.
Published August 9, 2023
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As already mentioned in my recent editorial, more and more Killer Whale specimens have been emerging lately. This awesome-looking split, sold as DIY kit at Yushakobo, has been around in Japan for a couple of months now.

Originally, it's a 28-key one-handed (right/left) device (the kit contains parts for one half only!) with a three-dimensional shape defined by acrylic pillars. However, by connecting two, you get a split keyboard.

Designer Taro Hayashi was kind enough to answer my questions about his inspiration, goals and preferences.

As a start, tell me a bit about yourself please.

I'm はやしたろう (Taro Hayashi), a common Japanese who likes to draw and play video games.

How did you get into the mechanical keyboard hobby?

When I was looking for a support device for drawing, I was attracted to QMK firmware because it allows saving settings on the keyboard itself. I've always hated software that sit in the taskbar or menu bar of off-the-shelf products. I also found out I could make it light up, so I immediately went to Yushakobo and bought Soyuz and Tone & Note, which are very well made and very popular. I recommend them for first-time builders because they can be used as a reference for making.

What do you do for a living by the way? Does your professional skillset help with keyboard design?

I don't really have any skills you could call professional. I am good with numbers and calculators, and guess my experience building Lego and Gunpla helps with keyboards too.

What parts of the rather diverse keyboard hobby are you involved in?

I like acrylic. It's hard, transparent, and sparkly. I'm really indebted to Yousha Kobo, Emerge+, and Elecrow for their cutting services.

I also like tactile switches and right now I like Everglide Seasalt.

But I'm most interested in optimizing inventory and expanding the Japanese community. Many Japanese people feel guilty about making money, but I believe that making money by doing good is fundamental to improving society. And with so many computers and tablets on the market every day, I believe keyboard making should become a more common hobby.

You offer a bunch of boards on What are some previous designs you’d like to highlight?

The Handyman MACROPAD is the best and has a very good reputation among those who use it. It has a lot of rotary encoders, which is great for auxiliary use, and it's column staggered, so you can't go wrong with the buttons you press. It can be used for just about anything, depending on the workflow of the person using it.

Pic: Handyman


We are getting to the Killer Whale, which is a pretty sick build even by Japanese standards. Tell us about your design goals and inspirations.

Killer Whale is directly inspired by Dactyl Manuform. That thing looks cool. Killer Whale would look similar if you'd remove the ADD Unit.

Also, there are so many people in Japan who use Keyball tilted on a stand, so I thought it would be simple and fun to have a tilted version from the start.

I decided to make it without using a 3D printer and PCBA so that it would be cheap and easy to duplicate, and it worked out well. It turned out to be a complex keyboard, though.

What about the abundance of pointing devices? And the modular thumb cluster and its angle? It looks very comfortable.

I tilted the trackball 45 degrees and it works very smoothly. At first I had set it at 60 degrees (30 degrees on the keyboard side, so it is at a right angle), but that caused the ball to wobble, so I loosened the angle.


I took care to make sure that the pillars for the balls and the PCB don't hit your fingers when you move the ball, and that the plates are positioned so that they don't collide with each other and are not too far apart. This is the point I want the assembler to see and touch.

Is this acrylic pillar approach your original idea or were you inspired by other builds?

My idea. I've been using 3mm spacers in other kits and noticed how well they work with M3 screws. I also like the slanted angle of the square nut to prevent it from falling off.



Why “Killer Whale”?

Took it from the name of a song by Smallpools. I like indie rock bands. My other keyboards use song titles and band names too.

This is not the easiest build, probably not for beginners. Even the build guide made me recall those "choose your own adventure" books of the ‘80s and ‘90s when you have to make choices along the way while reading. What was your target audience with this model? Any feedback from customers?

The individual tasks are not difficult, but their sheer volume requires patience. I've been getting good feedback from people who bought it right after it was released, probably because many of them like the process of making things.

Many people think that handwired soldering looks difficult, so I was thinking while making Killer Whale that it would be an opportunity for them to experience the three-dimensional structure and challenge themselves to create their ideal keyboard.

What does your home/work setup look like these days?

I love the ortholinear keyboards that I made, e.g. the On the 15, and have been using them ever since. Difference from others is that I use my index finger to type spaces. Japanese type a word and then hit space to select the appropriate Kanji, so I use space a lot and find it useful. And I don't like the complexity of layers, so I use 60 keys with a keymap that includes numbers and mods, so I don't need to press them at the same time too often.

Pic: On the 15

On the 15

Furthermore, I am a fan of Durock keyswitches. They have an indescribably luxurious feel. The recently released Blue Lotus is very good and I can't wait for the new silent tactile models like the T1 Shrimp. Plus my favorite profile is the Cherry profile. ePBT Ember I got recently was very nice. It would have been great if the base was pure white. I don't think there are enough white keycaps in the world. I like MT3 a lot too, but it's a bit high. So I'm looking forward to the MTNU profile.

I'm still working on the keymap for Killer Whale myself, first making it easy to use as a left hand device for drawing, then a stand-alone trackball for the right hand, then the main keyboard finally. Every time I receive parcels from JLCPCB, I assemble a board to make sure it works, so there will be more and more.

Any future plans?

I'm thinking of making a little macro pad, but now I'm in the mood to paint.

Killer Whale specs

  • 26-30 MX keys per half
  • hotswap
  • reversible PCBs
  • Raspberry Pi Pico controller (not included in the kit)
  • Optional trackball and OLED modules
  • Optional LEDs (SK6812MINI-E)

More info

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Published on Wed 9th Aug 2023. Featured in KBD #202308.



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