An Ode

Kei comes from the Japanese character 軽 which means lightweight, borne out of a desire for a return of the elusive HHKB HG keyboard, an all metal constructed case for the famed PFU Fujitsu Happy Hacking Keyboard designed by Professor Wada.

Almost all keyboard enthusiasts have tried the famed Topre switch in many forms, with a sizeable amount of wide-eyed inductees into this little cult getting their hands on the HHKB. The HHKB remains a decisive keyboard for some, a grail that returns the weary keyboard sojourner to their home for many and an overvalued membrane carrier for others.

I've bought and sold many HHKBs along the way, trying out the now extremely expensive HiPro (high profile) keycaps on them, swapping in and out different housings, lubing shafts like a crazed Mechanicus priest appeasing the Topre spirit. A well-used HHKB is an effective travel keyboard, one that allows the user to swiftly switch between work and play without taking up much weight or real estate.

Yet in the custom mechanical keyboard world, these traits are not always representative of the scene. Many adherents to this cult prefer heavier, heftier, larger keyboards. It's easy to see why; hefty keyboard kits means less shifting around and a greater consistency in typing sound and feel. Anyone who has modified the HHKB can tell you that the typing sound and feel does change substantially, and sometimes what works on one might not work on the other. The elimination of such inconsistency is the ultimate goal for many enthusiasts, to have the best sounding and feeling board for themselves. While the criteria for this may vary according to users, the goal is the same - endgame. A final keyboard that will call forth the songs of angels, herald the coming of all dreams and transport the user into a land of pure typing bliss.

Considerations

While salivating over pictures of the HG, I decided to ask bisoromi if he'd consider working on such a project. We started working on the KFE together, which also came about as I was reminiscing about the OTD Koala keyboard, one that I long traded away and came to regret. Bisoromi was enthusiastic to say the least, and with me adding on requests and tweaks he persevered in spite of my somewhat crazy ideas and worked out a modular construction that would both pay tribute to the HHKB HG and synthesise some popular ideas in the keyboard scene.

Another keyboard cult classic became part of the conversation: the OTD 356mini keyboard. The mini remains a keyboard I forever regret selling (I think you see a theme here), and the fact that I used to own 2 over a period of time made me yearn for it again. It was and still remains the best keyboard I've ever typed on. 55 gram springs on the smoothest switches known to my fingers, on a half plate. I realised two things after relinquishing my minis:

1. Tuning is essential. Good lubing skills, spring and switch selection can really bring out the best characteristics of a board.
2. Gasket + half plate = a feeling unmatched by other keyboards.

With that in mind, someone traced the mini's plate and case construction, and with some tweaks I handed off the files to bisoromi to work his magic. We compared different design approaches and bisoromi began to construct his idea of a HHKB style keyboard. Instead of using gasket strips like many contemporary keyboards, we decided to remain faithful to the original inspiration by sandwiching the plate and PCB with an O ring. While the 356mini suffered from inconsistencies that were sometimes quite baffling, we decided to modernise the plate and passed on the details to Hiney, who produced a USB type C PCB with modern quality of life upgrades such as quick changing of layouts (VIA) and ESD support.

As we progressed, we consulted many kind keyboard friends as well such as Zach from Keycult, who graciously helped us and allowed us the usage of their keyboard feet. This saved us a great amount of time and cost as we could rapidly approach prototyping phase without worrying about sudden increase in costs.

Philosophy

 In keeping with the tradition of the HHKB, I realised that an all aluminium construction with an aluminium plate might present a lighter keyboard while retaining the feel and acoustics that are characteristic of a custom keyboard. While my personal preference leans towards a lighter typing experience, we also decided to experiment with denser materials such as stainless steel. The idea is that those who prefer to leave their Kei keyboards at home can then enjoy a heftier keyboard suitable for a particular subset of users. More importantly, the inclusion of stainless steel also allows for an aesthetic differentiation while tweaking the Kei's acoustic properties.

Appreciation

In essence, the Kei is a dream come true for the team who worked really hard during the process.

• Much credit goes to bisoromi, who worked tirelessly to work out a seamless design that could accommodate tweaks as well.
• The brains of the Kei feature the work of hiney who gladly introduced hotswap additions to an already amazing PCB.
• Renders by thesiscamper who worked magic.
• Incredible product shots by artemie.  
• Keycult folks who were extremely generous with their suggestions and help as well. 

I've waited a long time and am absolutely delighted that the Kei is finally out. I hope you enjoy using it as much as we have working on it.

Caleb