This article covers PFU HHKB Professionalシリーズ キートップセット 日本語配列 無刻印 空 PD-KB420KTLBN.
Overview
PFU's HHKB Color Keycap Project has reached its fifth installment with this keycap set for the HHKB Professional series. The set is designed exclusively for Japanese-layout models of the HHKB Professional lineup, featuring a blank (unprinted) finish in a pale blue hue called "Sora" (sky). The key appeal of this set lies in its unprinted design: without any legends, the focus shifts entirely to the color and texture of the keycaps themselves. The clear, light blue shade evokes an open sky and brings a refreshing, airy feel to any desktop setup.
Connectivity & Compatibility
This keycap set is compatible only with HHKB Professional series models that use a Japanese layout. Supported models include: HHKB Professional JP HHKB Professional JP Type-S HHKB Professional BT HHKB Professional HYBRID Type-S HHKB Professional HYBRID HHKB Professional Classic Type-S It is explicitly not compatible with the HHKB Studio series. Users must also note that keycap replacement is a DIY task performed at their own risk, and the included manual should be followed carefully to avoid scratching or damaging the keycaps.
Product Info
Released in 2025 by PFU Direct, this set contains 69 replacement keycaps, a keycap puller tool, and an instruction manual covering the replacement procedure and key layout. The set is sold at approximately ¥9,240 on . As a customization accessory for the HHKB ecosystem, this product sits in the mid-to-high-end tier. It pairs well with previously released color sets such as "Sakura," "Wasabi," "Tanpopo," and "Fuji," allowing users to mix and match for a personalized look.
Best Use Cases
Existing HHKB Professional Japanese-layout owners: If you already own one of the compatible models and want to refresh its appearance, this set is ideal. The blank keycaps reward experienced touch typists who don't rely on legends. Desktop customization enthusiasts: You can swap just a few keys for accent or replace the entire set for a uniform look. Combining with other HHKB color sets expands your creative options. * Users curious about blank keycaps: This set offers a low-cost way to try a legend-free typing experience without buying a whole new keyboard. However, you must already own a compatible HHKB Professional body.
Things to Consider
This is strictly a keycap set — no keyboard body is included. You must already own an HHKB Professional series keyboard. The blank design means it is not suitable for beginners who rely on printed legends to locate keys. Replacement requires careful handling; improper use of the puller tool can damage keycaps or switches. Alternatives include PFU's own printed color keycap sets (White, Ink, Snow). If you do not specifically need a blank set, those offer a more practical, legend-included option.
