I Built a JIS Split Custom Keyboard with `sphh jp v2`

I bought the JIS split keyboard kit sphh jp v2 and accidentally stepped into the custom keyboard rabbit hole, so this post is a record of how I got there and what I think of it so far.

Background

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I had been using a Realforce R2 (non-silent, tenkeyless) for everyday work, and before I knew it I had owned it for almost eight years. Until recently I had no complaints at all, but after I spilled water on it, it started behaving as if the Fn key were stuck down.¹ It recovered after a night, but I had no idea when the problem might come back. That seemed like a good excuse to buy a new keyboard.

At first I considered buying a Realforce R4. However, recent Realforce models seem to be available only in silent variants, and I was worried that the typing feel would be too different from what I was used to.

That led me to seriously consider building a split keyboard, something I had been curious about for a while.

Choosing What to Buy

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Keyboard Kit

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I ended up with the following requirements for the kit.

On the other hand, I lowered the priority of the following points. I do not care that much about them, and there are very few split keyboards with a JIS layout to begin with.

• Whether it has F1-F12 keys
• Whether it uses a row-staggered layout

I had ChatGPT look for boards that met those requirements and did not appear to be discontinued, and apparently there were only four candidates.

• Radon_kb
• JP60 Split (Otaku Split v2)
• sphh jp v2
• Earth95s

Among them, I chose sphh jp v2, which was in stock when I bought it on 2026-03-15 and seemed simple enough to handle as a first board thanks to its relatively small number of keys and straightforward layout.

I was not confident in my soldering skills, and I did not even own a soldering iron, so I also paid for the assembly service.

Switches

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I did not want to choose switches without trying them in person, so I went to Yushakobo in Akihabara and tested several options. I focused on tactile switches in roughly the 45g-60g range that felt close to my Realforce R2, and among them Gateron Jupiter Switch Banana felt the best, so that is what I bought.

Keycaps

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There are not many keycap sets that support the Japanese JIS layout. The sphh jp v2 page also lists a few suggestions, but in the end I picked Acid Caps “Standard” Peri on Gray, which I found through a blog post by someone who had already built one.

Assembly

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I followed the official sphh jp v2 build guide. That said, because I used the assembly service, all I had to do myself was everything after “attach the screws and spacers to the top plate.” I thought the rest would go quickly since the soldering had already been done by a professional, but mounting the switches was more tedious than I expected, and I spent a while going back and forth on the key arrangement, so it still took about two hours in the end.

I had read a few blog posts from earlier builders who struggled during assembly, so I was a little nervous about whether it would actually work, but both halves worked perfectly on the first try.

Finished Build

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Here is the finished keyboard.

I like how stylish it looks.³ The purple keycaps and gray body go together nicely, and I think the result has a pleasantly premium feel.

Cost

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The total cost of this custom keyboard project came to 43,762 JPY. The breakdown is below. This total does not include the two USB-C cables I also needed.

In the end, it cost more than a Realforce R4, but I am happy with it and do not regret it so far.

Impressions

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This was my first split keyboard, so I expected a rough adjustment period, but it turned out to be surprisingly usable from day one. My typo rate did go up a little, but not enough to be genuinely stressful, and it already felt like something I would get used to soon.

On the other hand, once I started using it, I realized that when typing English I sometimes hit y and h with my left hand. In words like city and night, I had apparently been using my left hand for ty or gh, but the split layout no longer lets me get away with that. Since y and h are keys I already hit with my right hand when typing kana, I think I will adjust quickly once I retrain myself.

I am happy with both the typing feel and the appearance. Spending a bit more on the keycaps made the finished board look much better, and seeing it on my desk is satisfying in a way I did not quite expect. The typing sound, however, is louder than I had imagined, so I would hesitate to use it full-time in a quiet office. One of the nice things about custom keyboards is that I can swap the switches freely, so if I get the chance, I would like to try variable-weight switches or experiment with a few other options later.